So here is my attempt at Sketchup and my cabin thoughts. This is very rough, not nearly finished (no braces or purlins, joints, etc). This plan will be discarded as I have major difficulty in Sketchup modifying major elements.
(https://forestryforum.com/gallery/albums/userpics/30640/Cabin_test.png)
(https://forestryforum.com/gallery/albums/userpics/30640/Cabin_test_2.png)
I plan to have a full basement with a 4' metal access door and maybe a 9' roll up. Stairs at the opposite end come up between the bedrooms. In front of the bedroom on the left will be the bathroom and then the kitchen. Only the bedroom and bathroom walls are shown. I was working on a bent spacing of 12' 8' 8' 12'. The 8's would be the bathroom and kitchen with a common wall for water/waste. The actual bedrooms will be 10x10 because the closets will be within the bent area.
So now the problem, the span of 12' for the purlins is just too great - the purlins end up needing to be MASSIVE. At 8', they are manageable. So I figured I'd add another frame and split the 12's to a pair of 6's. The reason for the queen posts is to set up a space for the stairs and I just continued the elements forward. The posts will continue down through the basement. The great room is looking a little claustrophobic so I might make the pair of 6's into a pair of 8's.
Please, point out what I may be doing wrong or offer suggestions to improve.
Thanks!
Dimensions showing would be nice. Or post the plan in the sketchup section and we can download it and review.
What makes you think the purlins will be massive? Can you post your details such as snow loads, spans again, type of wood, spacing?
One center post would open up the middle of the floor plan. Speaking of floor plan, can you post that? Or a picture of that.
Jim Rogers
Jim,
Here are the particulars and a floor plan with dimensions (this is modified from the views above):
(https://forestryforum.com/gallery/albums/userpics/30640/Cabin_Floor_Plan_1.png)
Starting at the roof and working down:
My area has a snow value of 303 PSF. I will be doing a 12/12 roof, heavily insulated and a metal skin so my thermal rating is 1.2 and the roof snow load calcs out to just under 116 RSL. I added a 40 PSF live load even though I only need 30 per code.
Assuming that is correct, I make a guess of 2 foot on center purlins running 12 foot over the bedrooms and 8 foot over the front rooms (without the extra bent I've inserted on the floor plan). If I sheath the area with 2" pine or, preferably, cedar at 24 lb/cu-ft, I have an additional dead load of 4 PSF. My total load (RSL + Live + Dead) is 160 PSF not counting the insulation, metal and the purlin.
The beam calculator starts at the top asking for total load on the beam which I calculate as 160 x 24 square feet (12' x 2' spacing) = 3840 lbs.
Next it asks for the dead load. For now, I'm just using the planking at 4 PSF x 24 = 96 lbs. Beam span is 144 inches.
Width and depth of the purlin are just guesses until I pass.
Species I have is Ponderosa Pine and the building department basically says I have to build to #2 grade - so that is what I pick (under B+S).
I don't get a "pass" on all three until I go up to a 7x10 purlin! To me, that is big - granted that is a tremendous load it has to carry. ((However, if the physical spacing of the purlins is at 24" and you use the projected floor plan view spacing, that is reduced by a factor of 1.414 (45* angle). The load drops in proportion and the purlin rating becomes 5x9 -- is this correct???))
If I take it down to an 8 foot span (96") for the front parts of the cabin, my purlin size can drop to 5x8 - smaller, manageable.
Dropping to a 6 foot span (72"), I'm down to a 4x7 but for aesthetics since they all will be visible, I would keep it at 5x8.
Now to do this correctly, I suppose I would have to add to the dead load the weight of the purlin as well the rest of the roofing materials?
I'm hoping my use of the tool is erred is some way.
I could move the center post pair to the middle, but that complicates the placement of the supporting beams for the floor and/or lengthens the floor joists by 20%. I'm not down to that floor level yet so I'm not concerned with it at this point.
Also a question: For the sill beams, I'm thinking incense cedar (rot resistance?) 8" thick and wide enough to fit the posts (whatever they eventually calc up to be) plus enough to catch the bottom of my wall planking (1"?), the rigid foam insulation (5") and Hardi Plank exterior boards (Too many wood peckers!). That makes for a 8x14 with 6" hanging out side the foundation (as seen on my floor plan above) if the posts end up being 8x8s.
Just my opinion, but from an aesthetic perspective, that long narrow "hallway" on both the lower and upper levels would drive me crazy. I seriously doubt you need four posts per bent for only a 24 foot wide building. Try running your calcs with only a center post on the bottom level and widen the queen posts on the upper. I think that would help open up the space and not make it so claustrophobic.
ljohn:
thanks for posting the floor plan.
You said: "My area has a snow value of 303 PSF."
and: Is there a decimal point missing there? 303 pounds per square foot?
Later you say: "the roof snow load calcs out to just under 116 RSL."
and: Something doesn't look right here. If you have a 303 pound snow load how can the roof load now be 116? And what is the "R" in RSL? I'm assuming SL means snow load.
Also, both of your drawings don't show any purlins. What timbers are you calling purlins?
Did you omit them? (I see by your original post that you did. So I'll assume you know what a purlin is and where it is placed, between the rafters).
It's hard to verify your numbers without seeing the actual timber or the sketchup plan.
Having that many posts does seem like a lot.
And having one center post would make more sense if your floor plans will allow it by offsetting your hallway to one side.
If you want a centered doorway to the outside, then the outside bents can have four posts so you can do that. There is no reason why all bents have to have the same amount of posts.
Floor joists should run from bent to bent. Tie beams to hold up the floor joist would increase by some amount but they have to join some place in the middle unless you're going to buy or mill 24' long tie beams.
One thing I use to determine frame layout is the length of the longest piece of timber you can buy or mill. If you can't mill or don't want to buy 24' long timbers then don't design for them.
Are you buying timbers for the project or milling them yourself?
I want to discuss your plan more with you, but I'll wait till I hear back from you about these questions I have.
Jim Rogers
Jim,
I'm surprised that you didn't answer first! :o You're speed and thoroughness is always welcomed! OK, point by point.
Quote from: Jim_Rogers on January 20, 2013, 10:21:54 AM
ljohn:
thanks for posting the floor plan.
You said: "My area has a snow value of 303 PSF."
and: Is there a decimal point missing there? 303 pounds per square foot?
No, that is correct. If I go another 1,000 feet up in elevation, it is 450 PSF. This is from the County's web site specifically for my property. If I use another web site for the adjacent county (I am about 1,000 feet away from the boarder) it shows around 330 PSF. Look up the definition of "Sierra Cement". Keep in mind that two years ago, I had 19' of snow on my property.
Quote from: Jim_Rogers on January 20, 2013, 10:21:54 AM
Later you say: "the roof snow load calcs out to just under 116 RSL."
and: Something doesn't look right here. If you have a 303 pound snow load how can the roof load now be 116? And what is the "R" in RSL? I'm assuming SL means snow load.
I will have to go back and find the link but you have to convert the Ground Snow Load (GSL shown above - 303) to a Roof Snow Load (RSL). It takes into account your roofing material (rough holds snow, slick lets it slide off), roof pitch and thermal qualities.
Quote from: Jim_Rogers on January 20, 2013, 10:21:54 AM
Also, both of your drawings don't show any purlins. What timbers are you calling purlins?
Did you omit them? (I see by your original post that you did. So I'll assume you know what a purlin is and where it is placed, between the rafters).
It's hard to verify your numbers without seeing the actual timber or the sketchup plan.
I left the purlins off for clarity and because I'm lazy. :D I didn't see the point in drawing them since my drawing was done totally wrong (no joints), I didn't have a size yet and I was going to re-draw very soon. Yes, they will run between the rafters parallel to the ridge.
Quote from: Jim_Rogers on January 20, 2013, 10:21:54 AM
Having that many posts does seem like a lot.
And having one center post would make more sense if your floor plans will allow it by offsetting your hallway to one side.
If you want a centered doorway to the outside, then the outside bents can have four posts so you can do that. There is no reason why all bents have to have the same amount of posts.
Point well taken by you and others. I will re-design that aspect. Again, I was being lazy for the engineering calcs - transferring the loads to the foundation below. The point of the queen posts is to help reduce the overall size of the rafters that I'm assuming would be so huge without the rafter tie it would be ridiculous!
Quote from: Jim_Rogers on January 20, 2013, 10:21:54 AM
Floor joists should run from bent to bent. Tie beams to hold up the floor joist would increase by some amount but they have to join some place in the middle unless you're going to buy or mill 24' long tie beams.
I am building a mill and will be able to mill 24' - hence the width of the building. I want the floor boards to run the length of the building - I think that looks better, personal opinion. So, the joists need to run across the building. I'm going to do stick framing for the main floor so the floor joists may end up being placed on top of the sills and one or more beams running the length of the building. Other ideas welcomed :P
Quote from: Jim_Rogers on January 20, 2013, 10:21:54 AM
One thing I use to determine frame layout is the length of the longest piece of timber you can buy or mill. If you can't mill or don't want to buy 24' long timbers then don't design for them.
Are you buying timbers for the project or milling them yourself?
Attempting to use all my own cut wood - hence the question about the sill plates.
Quote from: Jim_Rogers on January 20, 2013, 10:21:54 AM
I want to discuss your plan more with you, but I'll wait till I hear back from you about these questions I have.
Jim Rogers
As always, Jim, I appreciate you sharing your knowledge and experience!
Thanks for your quick reply.
Ok, so now I understand your first floor framing layout of joists going across the 24' span from long sill to long sill.
My comments about the floor joist running from bent to bent were for the second floor framing.
We have two framing circumstances and we need to figure the framing for both. And we should state which framing we're talking about.
I understand your decision to not show the purlins on your first drawing.
I understand, now, your "R" snow load.
My next questions have to do with the type of roof system you have picked out.
You have discussed purlins with rafters. Which is known as a principal rafter/purlin roof system.
The other kind of roof system is the common rafter roof system.
I was wondering why you chose that roof system?
Do you understand the difference in assembling a principal rafter/purlin roof system vs a common rafter roof system?
A principal rafter/purlin roof system requires a lot more "rigging" equipment to erect the frame. You have to hold up or out one bent while you fly in the purlins between the rafters.
Here you can see a standing bent and some of the rigging used to hold another bent while the crane is used to fly in the roof purlins.
(https://forestryforum.com/gallery/albums/userpics/10095/1232/DSCF2111.JPG)
This makes assembling a frame a little more complex.
I don't want to "talk you out" of your ideas, I just want to understand if you understand the methods you'll have to use to assemble the design you are creating.
Jim Rogers
Quote from: Jim_Rogers on January 20, 2013, 12:16:53 PM
Thanks for your quick reply.
Ok, so now I understand your first floor framing layout of joists going across the 24' span from long sill to long sill.
My comments about the floor joist running from bent to bent were for the second floor framing.
We have two framing circumstances and we need to figure the framing for both. And we should state which framing we're talking about.
Agreed - for the main floor, the joists will go the short direction so the flooring can go the long direction. For the loft (second floor), the joists will go the short direction so the floor can run the longer dimension.
Quote from: Jim_Rogers on January 20, 2013, 12:16:53 PM
I understand your decision to not show the purlins on your first drawing.
I understand, now, your "R" snow load.
My next questions have to do with the type of roof system you have picked out.
You have discussed purlins with rafters. Which is known as a principal rafter/purlin roof system.
The other kind of roof system is the common rafter roof system.
I was wondering why you chose that roof system?
Do you understand the difference in assembling a principal rafter/purlin roof system vs a common rafter roof system?
A principal rafter/purlin roof system requires a lot more "rigging" equipment to erect the frame. You have to hold up or out one bent while you fly in the purlins between the rafters.
Here you can see a standing bent and some of the rigging used to hold another bent while the crane is used to fly in the roof purlins.
(https://forestryforum.com/gallery/albums/userpics/10095/1232/DSCF2111.JPG)
This makes assembling a frame a little more complex.
I don't want to "talk you out" of your ideas, I just want to understand if you understand the methods you'll have to use to assemble the design you are creating.
Jim Rogers
I understand the principle rafter/purlin roofing system and the associated assembly requirements. While the bent is bigger/heavier, it seems stronger to me with a better attachment of the principle rafter to the rest of the frame. What I didn't show it that I will have some eaves (size yet to be determined). I plan to hang a purlin out near the end of the principle rafter past the exterior walls. I don't see how to do that with timbers using common rafters - the necessary cuts for the bird's mouth seem more difficult (not to mention so many of them!) and leave little strength for an eve portion on the rafter. As you can see, I'm dealing with some substantial snow loads so I want to err on the side of robustness!!
I've read the three major timber framing books recommended by many here (once through) and will be reading them again.
And don't hesitate - talk me out of my ideas! I'm a complete novice on this scale of
furniture timber frame construction. ;) Please tell me your opinions on what are the better way to do things. Now is the time, before I start cutting!
My goals are simple: 1) have some fun building something that I can be proud of and my descendents can enjoy (i.e. comfortable and durable), 2) teach my son the joys of building (big things) - he already love to create on a small scale 3) utilize my own timber to the greatest extent possible and 4) have a nice place in the woods for my retirement - very soon 8)
OK, revised floor plan:
(https://forestryforum.com/gallery/albums/userpics/30640/Cabin_Floor_Plan_1b.png)
On the right are two bedrooms with closets shown as the tall rectangles. The 4' hallway is actually the stairs going down to the basement. I will have a pull-down staircase to go up to the loft in this space as well. I'm planning on the loft covering the bedrooms, bathroom and kitchen (to facilitate overhead lighting). The bathroom and kitchen have grown by 2 feet while eliminating the double post/hallway effect. To prevent issues with my stove pipe having to battle snow, I will follow the examples of cabins in my area - exit the roof at the peak (another (maybe poor) reason I didn't do ridge beam). Suggestions on placement of the wood stove? I'm thinking on the end of the kitchen bar rather than next to the refrigerator, the next post to the right.
I would like (but not a necessity) to have eaves in the long walls (top and bottom in drawing) - so I'm open to suggestions other than what I've stated above (principle rafter/purlin system), which is based on no experience.
Jim,
For calculating the weight on the purlins/principal rafters, do I divide the actual roof area supported by 1.414 (45°)?
You've got that big 12x32 space. Are you sure you wouldn't want to put a fixed staircase in--possibly in that lower right corner next to the bedroom closet? It could be an "L" in the corner and wouldn't take much space. It could double up (down to the basement and up to the loft). Seems it would be much nicer than pull down stairs. Also, you could take out the "hallway" and make your bedrooms larger. Just a thought.
Quote from: ljohnsaw on January 22, 2013, 01:13:16 AM
Jim,
For calculating the weight on the purlins/principal rafters, do I divide the actual roof area supported by 1.414 (45°)?
I haven't done a lot of designing using a principal rafter, purlin roof system as I am a traditionalist and usually use common rafter roof systems.
I'd have to do some research on that.
When I figure roof load, I figure for total load applied vertically:
(https://forestryforum.com/gallery/albums/userpics/10095/1232/Ridge_beam_cross_section.JPG)
And when my beam or rafter sizes have been checked by one of my engineers; they have told me that they are the right size. Not too big and not too small.
A couple of years ago, I wrote up a story about how to review a frame design.
It is here: https://forestryforum.com/board/index.php/topic,50714.0.html
Have you seen or read this story?
I didn't use any modifiers in my calculations, but maybe I should have.
I took one class at Heartwood school on timber frame engineering. I'll have to review my book and see if there is a modifier for roof purlins mentioned.
I don't actually right now recall any being used.
This is why I hire engineers to review my frame designs to ensure that I have the beam sizes correct.
Jim Rogers
Jim,
I had not seen that thread and I will read it later today - thanks. Your drawing above just puts my words/thoughts in picture form. The loads are all vertical so roof area needs to be calculated as vertical vector. I need to pull out my Statics book I used in school 34 years ago. :P
Ok, Jim. I read through that thread - very interesting and I totally get the math. However, I'm just a bit confused on your use of the timber calculator.
The first item is minor - I read somewhere that the a timber USED as a beam/stinger should have dimensions of AT LEAST 2" difference. In that post, you stated it should be MORE THAN 2". Not that big of a deal but you use that in your decision on using the calculator.
That is the more confusing to me. I see the definition of Post and Timber (P+T) as a vertical element and Beam and Stringer (B+S) as a horizontal-ish member.
P+T would be less concerned about deflection along its length and more about compression down the grain. B+S would be the opposite.
Unless I really read the thread incorrectly, it seemed that the 12x13 beam was being evaluated under the P+T criteria. Is that really how it is supposed to be used?
Then again, does it change the answer when you flop the wood type (B+S:P+T) from one to the other? I'll have to try it tonight.
Quote from: ljohnsaw on January 22, 2013, 05:03:06 PM
The first item is minor - I read somewhere that the a timber USED as a beam/stinger should have dimensions of AT LEAST 2" difference. In that post, you stated it should be MORE THAN 2". Not that big of a deal but you use that in your decision on using the calculator.
From my grade rule book, published by NeLMA; Section 6, paragraph 25.0 Beams and stringers (70.00 WWPA) 5" and thicker, width more than 2" greater than thickness. end quote.
To me that say more than 2" greater, so 2" greater isn't a Beam and Stringer. It is a post and timber. If it was 2 and 1/8" then it would be greater. But 2" to me is a post and timber category.
Quote
That is the more confusing to me. I see the definition of Post and Timber (P+T) as a vertical element and Beam and Stringer (B+S) as a horizontal-ish member.
Right, if the timber is greater in height/width then thickness then it is assumed that the user will place it horizontally or on an angle like a stair stringer, such as rafters.
Quote
P+T would be less concerned about deflection along its length and more about compression down the grain. B+S would be the opposite.
Right.
Quote
Unless I really read the thread incorrectly, it seemed that the 12x13 beam was being evaluated under the P+T criteria. Is that really how it is supposed to be used?
If that thread says it's a 12x13 then it's in the P+T category, whether or not if it's used vertically or horizontally.
Quote
Then again, does it change the answer when you flop the wood type (B+S:P+T) from one to the other?
It may pass in one category but fail in another due to design values being different.
I hope that helps you some.
Jim Rogers
Jim,
It does help, those are the rules. However, in my engineering mind, when I see something horizontal, you need to evaluate it as a horiontal member. Without knowing what the mechanics are behind Don P's calculators, my mind will be forever in unrest! I had the same problem in sadistics Statistics - they would say, just do it this way. Calculus I got. I need to play with it, do some further research to put my mind at ease. I want to be able to be 100% confident (able to describe how I came up with the values) when I talk with the engineer that will be reviewing my building plans.
Thank you
When I first discussed my designs to be reviewed by one of my engineer's, I asked if he wanted me to show him my "work". That is how I came up with the numbers I used.
He said it was his job to come up with the numbers and not just read my work.
That way he'd be satisfied that the numbers are correct.
When you have your design done, and you're ready to go to your engineer, if you need any further information then let me know and I'll help you with all the data I can to give to him.
He should be using the NDS values which are what's in DonP's calculators.
I have the book and use that as well as the online calculator.
Maybe tomorrow, I can tell you about DonP's calculators and my work with him.
Going home now after a very cold day outside at the mill.
Jim Rogers
More information was volunteered by the planning department (a plan examiner) which make the design easier (less decisions for me because of the requirements):
For Heavy Timber construction, they have a whole section on construction criteria. Some seems a little oddly worded (asking them for clarification) and seemingly excessive but not too burdensome requirements.
Ex:
602.4.2 Floor framing – States that beams & girders need to be no less than 6x10. No mention of joists – filling in the spaces between the girts to a reasonable span for the floor boards.
602.4.3 Roof framing – in the center of the paragraph, it states the "other roof framing, which do not support floor loads, shall have members not less than 4 inches in width and not less than 6 inches in depth". I'm assuming that is referring to purlins and/or common rafters.
602.4.4 Floors – Need a subfloor of at least 3" thick nominal (2-1/2") T&G boards and the 1" finish floor (3/4") Regardless of the joist spacing? That's a lot of floor! Since it looks like I will have to do a sub-floor, I can run the "joists" the short way from bent to bent, which may be at a minimum, 6x10s.
602.4.6 Partitions – ...not less than two layers of 1-inch matched boards... What are "matched" boards? Can anyone comment on what they had to do for interior walls in a permitted structure? I think what I may do is for the bedroom walls where visible to the common room is to place the purlins on the main room surface so it matches the exterior walls in appearance. I guess I cannot have a "plumbing" wall between my kitchen and bathroom! The shower pluming will be "hidden" behind the refrigerator!
Other parts mention the outside wall cannot have any open cavities, that is, no stud walls, which is not a problem for me.
You guys are thorough. And its well thought out.
Here is a picture that might help with the conversation:
(https://forestryforum.com/board/proxy.php?request=http%3A%2F%2Fmedia9.dropshots.com%2Fphotos%2F525558%2F20130125%2F184533.jpg&hash=e047f96509443453289d57010323b5363a23f209)
In my opinion there are too many bents. If I might add a suggestion.
- I would delete B and F.
- Move C towards A on the other side of the bar. This should get you to around 14'.
- Establish a ridge
- Entertain the idea of principal purlins with light commons on top
I don't know what your post x-sections are, but if you have to resize the whole frame a little larger but with less bents.
Just food for thought.
I drew the plans up in Sketchup. How do you add decent looking text? I could not do it very well. I have a ton of new information and will be re-working my ideas. I already removed B and F and changed the center two posts into one except at A, E and G per Jim's suggestion. As far as bent spacing, the snow loads are such that at a 12' spacing with purlins spaced at 2', the purlins are required to be 6x9s. If I push out to 14', they will need to be even bigger. I'm using Ponderosa pine - no hardwoods available. Stay tuned - I will detail my sizing of wood calcs soon.
I have Photoshop. ;)
No doubt you two will figure this out. Just keep in mind that your purlins don't have to flush out with the top of the principal rafter.
(https://forestryforum.com/board/proxy.php?request=http%3A%2F%2Fmedia11.dropshots.com%2Fphotos%2F525558%2F20130125%2Fb_171251.jpg&hash=0c29ac5dc695c3468aae31805e9f44b9c8975dc0)
Cheers. I look forward to this thread. Good one.
^^^^
:D I have two accounts! Accidently logged in with new one. Then I remembered my password..
I'll have to think about doing the purlin "proud" of the rafter.
OK, here goes, please correct me (Jim) if I have this wrong -
The cabin will be 26' wide by 49'-4" long. In the view below (without the purlins) you can see I'm going for a queen post design to help split the principle rafter span in two.
(https://forestryforum.com/gallery/albums/userpics/30640/Cabin_2012-01-26.png)
I have not calculated the tie beam size at this time.
The particulars for my location:
Dead load on roof - 30 psf, Ground Snow Load - 303psf with a calculated 116 psf RSL (Roof Snow Load) on my 12/12 sloped metal roof with no obstructions in a clear area.
The bays are four 8' and one 12'. The roof planks (and walls) will be 2" T&G Incense Cedar which has a weight of 4lb/bd-ft (as does the Ponderosa Pine to be used for purlins and rafters/beams). The purlins will be spaced at 2' on the slope. The calculations for the purlins - the roof area in question will be 24 sq-ft actual and 16.97 projected (for snow and live load).
To calculate the purlin, I need the purlin weight (guess at 6x9) for the biggest bay (12') and it is 216lbs. The wood planking is 48 sq-ft and comes to 192lbs with a total dead load of 408. The live load of 30psf on the 16.97 is 509lbs and the snow load comes to 1,969.
Plugging in the beam calculator:
Total load on Beam (purlin) - 2,377 lbs
Dead Load on Beam - 408
Span of Beam (inches) - 144
Width of Beam - 6
Depth of Beam - 9
Select Species and Grade - #2 Ponderosa Pine B+S
This gives me a pass on all three. The Section Modulus Required is 71 and I hit 81, the deflection is just under 1/4", and the section required for shear is 13.7 and I hit 54. The bending was the big problem.
For the principle rafter, normally it would carry the load of 1/2 of each adjoining bay. But with the queen posts, I'm dropping the load in half. So, 1/4 of the area of the 12' bay:
Dead load of 408 x 6 (purlins for entire rafter) / 2 (half the bay) / 2 (half the rafter) = 612lb.
Total load (from 12' bay) is 2,377 x 6 / 2 / 2 = 3,565lbs
Doing the 8' bay, Dead load of 272 x 6 / 2 / 2 = 408lbs
Total load 1,585 x 6 / 2 / 2 = 2,377lbs.
Add to both dead and total loads the weight of the (1/2) rafter = 192lbs.
Grand total dead load is 1,212 and grand total total weight is 6,134lbs
Plugging in the beam calculator:
Total load on Beam (rafter) - 6,300 lbs (rounded up)
Dead Load on Beam - 1,400 lbs (rounded up)
Span of Beam (inches) - 72
Width of Beam - 8
Depth of Beam - 12
Select Species and Grade - #2 Ponderosa Pine B+S
This gives me a pass on all three. The Section Modulus Required is 94.5 and I hit 192, the deflection is just about zero, and the section required for shear is 36.4 and I hit 96.
Since this is way over-kill, I could drop down to 7x10 but I'm worried I would not have enough meat to plug the purlins into it.
Thoughts and comments welcome.
If you are entering a dead load then remove it from the live load. You're adding it twice, I think.
Live load is your snow load only.
Dead load is all your roofing materials, and the timbers themselves.
You may need to "run" your numbers again.
When you have the calculator open, you can select "save as" and put it onto your own home computer so that you don't have to be online at the forum to use it.
For your information.
I don't have any weight values on Ponderosa pine so I'm not sure if that is correct or not. I'll assume you have done your research and that they are correct.
As far as I can see other then the double counting the dead load, your process looks right.
Jim Rogers
Quote from: Jim_Rogers on January 27, 2013, 10:31:59 AM
If you are entering a dead load then remove it from the live load. You're adding it twice, I think.
Live load is your snow load only.
Plus the 30psf required by the county?
Quote from: Jim_Rogers on January 27, 2013, 10:31:59 AM
Dead load is all your roofing materials, and the timbers themselves.
Maybe I need clarification on the calculator. What is the "Total Load on Beam", first box - is that just the Live Load (30psf + the snow load)? I take things too literally. To me, Total means total.
Quote from: Jim_Rogers on January 27, 2013, 10:31:59 AM
You may need to "run" your numbers again.
When you have the calculator open, you can select "save as" and put it onto your own home computer so that you don't have to be online at the forum to use it.
For your information.
I don't have any weight values on Ponderosa pine so I'm not sure if that is correct or not. I'll assume you have done your research and that they are correct.
As far as I can see other then the double counting the dead load, your process looks right.
Jim Rogers
Thanks, Jim - I anxiously await your response.
Also, I messed up a little on the dead load. The purlin sections I stated 6 for the span. In plan view yes, 2' on center, but for 2' on center on the roof slope, I need 41% more (2.47 more purlins, so round to 3). My dead load on the roof area for the rafters goes up a little.
John:
If you use the first calculator for uniformly loaded beams, now that you know the values for grade #2 ponderosa pine, you would enter the total load on the beam.
I don't know why DonP added the dead load factor in the second calculator.
But, if you understand that the gravity load is vertical, and the dead load is in the slope of the roof plane, (which means it is higher then if the roof was level) you can add to the live load the adjusted dead load to get one number; which would be the total load. And then use the first calculator that asks for one load only. Then you won't be double dipping, and over sizing your timbers.
Jim Rogers
Quote from: Jim_Rogers on January 27, 2013, 10:31:59 AM
If you are entering a dead load then remove it from the live load. You're adding it twice, I think.
Live load is your snow load only.
Dead load is all your roofing materials, and the timbers themselves.
You may need to "run" your numbers again.
When you have the calculator open, you can select "save as" and put it onto your own home computer so that you don't have to be online at the forum to use it.
For your information.
I don't have any weight values on Ponderosa pine so I'm not sure if that is correct or not. I'll assume you have done your research and that they are correct.
As far as I can see other then the double counting the dead load, your process looks right.
Jim Rogers
I went back to run the numbers again. For "Total" load, I put in the snow + live load for the area. Dead load is just the wood (factored up for the actual roof area - 9 purlins total in 12 feet of "run" on the rafter). For the actual purlin calculation, I still fail on a 5x7 so I'm sticking with a 6x9.
The old numbers were:
This gives me a pass on all three. The Section Modulus Required is 94.5 and I hit 192, the deflection is just about zero, and the section required for shear is 36.4 and I hit 96.
The new numbers:
This gives me a pass on all three. The Section Modulus Required is
92.95 and I hit 192, the deflection is just about zero, and the section required for shear is
35.74 and I hit 96. (for an 8x12). I do pass with a little margin with a 7x10. It might look odd to have 6x9 purlins hanging off that so I'm leaning toward the 8x12. Besides, with the climate change, we will only be getting more snow!
I'm still "safe" :D
Jim, by Save As, are you referring to the File menu for explorer?
Quote from: Jim_Rogers on January 27, 2013, 11:02:05 AM
John:
If you use the first calculator for uniformly loaded beams, now that you know the values for grade #2 ponderosa pine, you would enter the total load on the beam.
I don't know why DonP added the dead load factor in the second calculator.
But, if you understand that the gravity load is vertical, and the dead load is in the slope of the roof plane, (which means it is higher then if the roof was level) you can add to the live load the adjusted dead load to get one number; which would be the total load. And then use the first calculator that asks for one load only. Then you won't be double dipping, and over sizing your timbers.
Jim Rogers
Jim, when I use the first calculator with the Ponderosa values, I fail on the 6x9 purlins. The Section Modulus Input is 81 for both. The first calculator gives me a value required of 86.6 and the second of 74.3. If I up the depth of the purlin to 9.5, I'm good in both calcs.
John:
I think you may have it right now, but I haven't personally ran your numbers.
When you have it all designed; your engineer will verify and make suggestions to your sizes.
I'm sure he is aware if the loads in your area if he's a local that has done it before.
Jim Rogers
Hi John,
I have been following along this entire time, and I track with 90% of what Jim is trying to say, (he is faster and better at this "prelim" engineering stuff than I am.) Jim has hinted at a number of design changes to your frame, even with your extreme snow loads, I think you will be able to, with Jim's and FF guidance, come up with a workable and aesthetically pleasing design. Jim last post about your PE is also very true. Good luck and keep asking your questions.
Regards, jay
Ok, some questions:
I'm doing princple rafter/purlins - the purlins will be 6x9 two foot on center fitted into 8x12 rafters. I'm thinking a 6" wide x 4" tusk tenon? Also, how do I finish the ridge? The roof sheathing/planks will be 2" stock.
Speaking of purlins, what is the typical vertical spacing on walls and what is the typical wall plank thickness (2")?
For the top "purlin", I'm thinking upping the size to a 6x8 so I can attach bracing to it.
Thanksi
Hi John,
For me, as a designer, I really need to know what someone likes and doesn't like, before I can give them good advice. It gives me the parameters and lets me know if I can really be of service, because there personal style may not fit how I design.
One thing, I have noted, is that if you went from a 12/12 to a 16/12 pitch, you could lesson the size of your materials, if you would like. Now that is just one example of a style nuance. Most of my work is based off the different elements of the "golden mean," like the 3-4-5 tangle. The difference between 45 and 53 degrees isn't that much, but it does make the math different for loads and it makes your numbers for measuring much easier. Not to mention that 16/12 is a classic pitch on traditional mountain architecture, form the Carpathians to the Niseko range of Hokkaidō.
On your roof purlins, you could go with the simple spacing of the purlins...or, do the high end design maneuver of harmonic progression. take the max distance the math states is required for your purlin spacing, then apply a HP equation. Some are hard some are easy, like: 1/a, 1/(a+d), 1/(a+2d), 1/(a+3d), etc. The widest spacing is from the rafter plate to the first purlin, the next is closer, and so forth. This gives the room a since of space that you are only aware of subconsciously, but you know something is happening.
Have you considered the very traditional look of "principle rafter, principle purlin. Many Eastern European homes have this. Then you have common rafters that create the roof plain. It is classic, beautiful, and traditional. Plus it is much easier to build.
With 2" thick planks, you are moving into the realm of "plank house," timber framing. You don't need purlins, others than for the Header and sill of your fenestration plan, (windows.)
Regards, jay
Quote from: Jay C. White Cloud on January 28, 2013, 06:18:53 PM
Hi John,
For me, as a designer, I really need to know what someone likes and doesn't like, before I can give them good advice. It gives me the parameters and lets me know if I can really be of service, because there personal style may not fit how I design.
One thing, I have noted, is that if you went from a 12/12 to a 16/12 pitch, you could lesson the size of your materials, if you would like. Now that is just one example of a style nuance. Most of my work is based off the different elements of the "golden mean," like the 3-4-5 tangle. The difference between 45 and 53 degrees isn't that much, but it does make the math different for loads and it makes your numbers for measuring much easier. Not to mention that 16/12 is a classic pitch on traditional mountain architecture, form the Carpathians to the Niseko range of Hokkaidō.
I've thought about steeper roof pitches but I don't like the appearance of wasted space (way up there) and the math becomes more complicated. I'm all about keeping it simple so I don't make mistakes.
Quote from: Jay C. White Cloud on January 28, 2013, 06:18:53 PM
On your roof purlins, you could go with the simple spacing of the purlins...or, do the high end design maneuver of harmonic progression. take the max distance the math states is required for your purlin spacing, then apply a HP equation. Some are hard some are easy, like: 1/a, 1/(a+d), 1/(a+2d), 1/(a+3d), etc. The widest spacing is from the rafter plate to the first purlin, the next is closer, and so forth. This gives the room a since of space that you are only aware of subconsciously, but you know something is happening.
Now that sounds interesting. I'll look into that. If it means one extra purlin, so be it. Since the space is getting narrower (less load), I would suspect the purlins would be getting lighter as well. That sounds intriguing, but pretty complicated, cut wise.
Quote from: Jay C. White Cloud on January 28, 2013, 06:18:53 PM
Have you considered the very traditional look of "principle rafter, principle purlin. Many Eastern European homes have this. Then you have common rafters that create the roof plain. It is classic, beautiful, and traditional. Plus it is much easier to build.
Googling principal purlin is not very fruitful. I did see some images and from what I saw, you could classify them as beams supporting the rafter system mid-span or every 1/3 span and so forth? If that is not right, can you provide a link or a picture showing what this is?
Quote from: Jay C. White Cloud on January 28, 2013, 06:18:53 PM
With 2" thick planks, you are moving into the realm of "plank house," timber framing. You don't need purlins, others than for the Header and sill of your fenestration plan, (windows.)
For the walls, I'd like to go 1" boards if that is acceptable (to maximize the yield from my logs). Drawing up my plan, there is not much room for purlins when you consider windows. I'm thinking 2 foot from the floor is the window sill, windows being at least 4 foot tall, that only leaves 2 feet to the top of the wall. Is a 4 foot vertical span too much for 1" boards and a wall that will have about 5" of rigid foam and vertical strapping for clapboards? I suppose I could do "stub-purlins" to fill the space between the posts and the window frame, halfway up the window.
Quote from: Jay C. White Cloud on January 28, 2013, 06:18:53 PM
Regards, jay
OK, here is my drawing so far in SketchUp. It does not have the main beam/support running the center of the cabin in the basement. Just pretend it is there. I have not run the calcs on the beams above and below the queen posts, yet. The basement openings face West.
Funny how the building keeps getting bigger and bigger! The loft area needs to cover the large bay (two bedrooms and stair case going down) and the north half of the next two bays (bath and kitchen as you head west from the bedrooms). I put in the loft extending more than necessary just to see how it looks.
I'm not sure where the attachments go, but if your looking, the name is "LJohnSaw Cabin 2013-01-28.skp"
Thanks in advance for your comments.
Hey John,
I didn't want to do this fast but I may not get a chance tomorrow, so I apologize in advance for my lack of normal detailed response.
QuoteI've thought about steeper roof pitches but I don't like the appearance of wasted space (way up there) and the math becomes more complicated. I'm all about keeping it simple so I don't make mistakes.
The different between 10/12 and 16/12 is a lot but not between 12/12 and 16/12. You also choose not to have the heated space go all the way to the ridge. Having a small flattened facet near the apex of you room is often seen as an interesting architectural detail.
Second, the math of a 12/12 is much more complicated than a 16/12, (which is a 3/4/5 triangle.) The one you need a calculator for the others is empirical or geometric and dimensions of the sides of the triangle are reciprocal. Try doing a little trig and compare the two, I think you see the simplicity of one over the other.
QuoteThat sounds intriguing, but pretty complicated, cut wise.
It is about the same and maybe easier in some cases.
QuoteGoogling principal purlin is not very fruitful.
Go to Google then hit "images," then enter:
principal rafter and principal purlin you will see a number of different configurations. Also try
cruck frame in images. This is the folk style that principal rafter and principal purlin came from.
Now your wall we need to talk about later, you have some choices that you may not have considered, like wall trusses, which you can find a lot of information on right here on the FF, just do a search.
Regards, jay
In my drawing, I have the purlins set so their top face is in line with the rafters - that is, the 6x9 purlin is set at a 45° angle. Looking at the forces of gravity and snow load, is that orientation correct or do the purlins need to sit "vertical" so the depth can effectively handle the load that they were sized for?
For the ridge, should the top-most purlin be sized as a 9x9? and how should I attach it without removing too much from the rafter ridge joint? Make the purlin be the "peg" (tusk) holding the top joint together, with it being housed a little?
Your gonna have to draw that one for me, I can't really see it the way it's described and these sizes are all way off of what I normally see, even in Colorado. I do think from your description the purlin is in the correct orientation for your application.
Regards, jay
Jay,
Here is the latest with the top "ridge purlin" in place. When you say the way I described, as in my plan (at 45°) or that they need to be vertically orientated?
Thanks,
The way you have it in the attachement is the normal orientation. Does that help? ??? ;D
Yes, thanks. Its the engineer in me that says it should be in a "flat" orientation to get the strength as calculated by the tables/beam calculator. Any thoughts on the ridge piece (attachment)?
John,
Good job on your drawing!!
I have some comments and suggestions...
You have 6x9 purlins 24"oc...I didn't run the numbers but that spacing seems to "crowd" the purlins a bit. If you could spaced them further apart you would use less material, have fewer mortise/pockets to cut and it wouldn't look as "busy" in the roof.
What do you have holding the mid-span of the first floor?... and is the spacing and sizes of the joist your final version?
You have two different joist patterns in the upper floor...the two shorter bays have a the joist farther apart and all seem small in comparison to the other large timbers in the frame.
Your windbraces/diagonals seem short. Have you thought about changing them from 24"x24" to 36"x36"? If you do decide to go larger you can offset the amount that they will intrude into the usable living space by making the frame taller (sidewall and interior posts) and raising the tie-beams.
The amount of "head room" upstairs in the loft seems short at 6'6", without any floor system. 6'8" off of the finished floor would be the same as a doorway opening...could you add some length to the tops of the sidewall posts above the tie-beams?
And the last thing I will leave open for others to comment...
Do principle rafter and common purlin systems need any wind-bracing from either end-wall? Do the multiple joints and decking hold it rigid enough? These designs always make me nervous. :-\ That is why I like ridge beams with wind-bracing... ;)
Keep up the good work!!
Rooster
Im on my first cup of coffee and when i read the title of the thread i thought it said (messing with sasquach) :o. See what you young guys got to look forward to ;D.
Rooster,
Thanks, lots of great comments - just what I'm looking for.
The headroom upstairs is an issue. I was worried about extending the post too far up past the tie beam. But that was before I put the rafter tie in place. I should push up another foot or so but not sure how to do it in sketchup without totally screwing up my work so far!
The purlin spacing was driven by trying to keep the size down on the 12' bay. I could rework the numbers and try 30" and see if I can get that to work. I'm pretty sure 36" will be crazy big.
Yes, not shown but there will be a big beam running the length of the cabin in the middle. The floor joists are sized for the 12' span.
The spacing of the second floor joists is because of the 8 vs. 12 span and the width of the boards change as well to save wood. The 12' joists (bedroom ceiling) will not be visable from the 8' bays (great room).
I put the top beam (girt?) Between the bents as a window header and a place to put bracing. I could/should put some bracing from the mid purlin down to the queen post, you think?
Is there much gain in strengh going up from 24x24 to 30 or 36? A triangle is a triangle. Though the larger the size, the more forgiving an error of 1/16" in your cuts. I suppose I could do curved bracing as I do have some interesting trees to choose from.
i
ljohnsaw,
A lean towards larger diagonals because the smaller the "triangle" the closer the fulcrum is to the joint. You will have a very large roof surface with a lot of wind load trying to push the building over. One 4x8 sheet of plywood in a 20 mph wind is hard to control..now multiple that by 31 times.
I am posting a different frame design (just an option for you to look at) that uses principle purlins and common rafters, but much of your frame sizes are the same... the bents are 12' apart and there is more head room both down stairs and up. It is more of a concept with no joints drawn.
Rooster
(https://forestryforum.com/gallery/albums/userpics/15824/LJohnSaw_Cabin_2012-01-29_CR12D.jpg)
Roster,
So I took your idea and ran with it. I calculated the loads and sized things. I put up a ridge beam because of the loads. Each 12' section of the ridge beam and principal purlins have a load of 10,000 lbs, hence the size of 8x15. The "sill" purlin (forgive me, don't have the names down yet), only has 5,000 lb so a 8x12 works there. The rafters are 5x9 36" OC. I could get away with 5x8s if I care to. The corner posts are 8x8 and the center ones 10x10. The mid-wall posts are 8x10 because the beams running across are 10x16s to carry the load from the principal purlins (10,000 lb mid-span). I've threw in some bracing but too tired now to finish.
I need to figure out how to add components to a named component. Also, I'm having trouble with the layers - try turning things on and off and watch what happens!
I have been following along, your new design with Rooster's influence is a vast improvement and has much more balance and symmetry. There is some horizontal through brace methods you may employ to avoid the oblique bracing. Also you have some other configurations that would also be horizontal in nature that could stiffen the frame. Again this update looks much better.
I am still not "feeling" the math on this. I haven't ran numbers completely, I'm just running on experience. If I didn't better, I would think you had calculated everything for a flat roof? Could you put your math for the 45 degree roof pitch compensation in an attachment with some of your other numbers. Slopes like that usually only catch wind loads and 30% or 50% of snow loads, if memory serves.
Thanks for sharing everything with us. You have been great about taking feedback and incorporating it into your design. When you are done, I think you will be very happy.
Regards, jay
Jay,
Thanks for your feedback. I am not happy with the looks of the bracing yet. I just threw some on to see how it would look. As far as the snow load, go back up in this thread (I thing I stated it). The ground snow load is 303 PSF for my area. On a 45° metal roof it drops all the way down to 116 PSF RSL (roof snow load). I have rounded up - for instance, the weight on one principal purlin calc'd out at 9,700 or so. I rounded up to 10k. The rafters at 5x8 had a pretty good margin, but I decided a 5x9 would look better against the larger members without using too much more wood. My braces are just a stab at 3x5 - perhaps someone could suggest a rule for appropriate sizing with the other timbers?
As far as wind load, I have no clue what do do there. For additional bracing and design look, I'm thinking of running the roof planks at an angle - either 30 or 45 degrees. What do you all think? How do I calculate the thickness of the roof planks? I'm just assuming 2x stock, T&G. I don't see anything in the toolbox for that. The rafters are at 36" spacing. I could go to 48" with the same size rafters but that just seems too far for my comfort.
Quote from: ljohnsaw on January 30, 2013, 11:40:03 AM
I should push up another foot or so but not sure how to do it in sketchup without totally screwing up my work so far!
Whenever I want to try something new with a model without losing or potentially corrupting my work, I "save as" another file name describing the changes I'm making (i.e. working model, extended posts, 48 inch rafter spacing, etc). This ensures that I can always go back to the master copy without having potentially lost any progress. Also, I always keep each subsequent revision as a separate file (named rev 1, rev 2, etc) until i arrive at the final product I am happy with, so I can always go back to a previous revision and try something new. It also allows you to open more than one instance of sketchup and compare models side by side as well as copy and paste objects or groups from one model to the next.
Dan
John,
I hope you are having as much fun designing and engineering this building as we are watching you learn through the process...thanks for including us.
You are really starting to dial this "pig" in!!
So, I want to play "devil's advocate" for just a second and have you re-visit the snow load requirements. The roof systems keeps growing even to the point it looks like it is even outgrowing itself...Eh? :D
I like the addition of the ridge beam, but it is only supporting the top 25% of both sides of the roof...right?
The purlin will take more of the roof load (50%), with the top-plate taking the last 25%.
Your rafters will only have to be big enough to span the distance from the peak to the purlin or the purlin to the top-plate.
I still would encourage you to go longer on your diagonals from your posts to the underside of your tie-beams. (wind-load stiffener)
The posts that support your ridge beam are now in your living space...ugh!
Here is a picture of a simple truss that you might be able use to carry the ridge beam without the additional posts.
Good job!
Rooster
(https://forestryforum.com/gallery/albums/userpics/15824/pavillion03_2D.jpg)
Rooster,
Yes, it is getting big but lots of fun. I understand your concern about the posts in the living space, but, there will only be one...
Starting from the east end (the openings in the foundation are on the west end), there are two bedrooms and that middle post will be the ends of walls dividing up that space. The next post west will be part of the dividing wall making up the kitchen/bath area on the north side of the building. It will only be the next post west that will be in the living area that will be ell shaped. It will help deliniate the space of the "dinning room" in this open plan. The second floor is just a loft area at this time so the posts up there don't bother me. It will be easy enough to incoporate into wall in the future if I want.
Yes, I totally understand the loading. While the ridge beam is "only" taking on 25% of each side of the roof, that still amounts to a 10,000 lb on each 12 foot beam. A scary amount of load!
I can go through the exersice and post my steps again on this roof design. I would hope that someone could point out an obvious error in my logic and everything could shrink! Looking at other cabins in the area gives me some validation in my calcs - they are built very stout.
OK all,
Here is my latest - haven't had a lot of time with work getting in the way and all. ::) I laid out my first floor floor joists. My calc says 3x12 36" OC will hold themselves, 2" flooring and 40 PSF live load. I put them at 35" so I would get a joist either side of the center posts. Should I bother with that or just run the pattern at 35" all the way down the cabin? I'd have to put some blocking at the posts to hold the ends of the flooring. I'd save 2 or 3 joists doing even spacing.
I did a little messing around with the bracing and you can see where I'm thinking based on the first bent. I upped to 36" where I could but I need some ideas about the principal purlin bracing going across the cabin (short dimension). I have a lot of them but thinking I could do with less. The cross beams in the center 3 bents are 10" wide so I suppose I could do a crossing brace. That way I could lengthen them and put the brace into the outside purlins instead of the outside post - good idea or not?
I need a little help with SketchUp - When I put some of the braces in, I sometimes forgot to open the bent "component" so some of the braces are on their own. I have layers so turn that on and play with removing each layer. Is there an easy way to add items into an existing component? Also, I was watching a YouTube tutorial but the guy was using shortcut keys so I'm not sure what all he was doing. There is something about selecting an element from a component and making a unique copy - one not associated with the component. Anyone know how to do that? For instance, I design a brace in my end bent (component) and want to include it in my middle three bents, which are component clones.
John,
I made some suggestions on "bent" wind bracing. Each bent should probably have the same diagonal configuration. (see photo)
(https://forestryforum.com/gallery/albums/userpics/15824/LJohnSaw2BCabin2B2012-02-03CR2D.jpg)
Having a diagonal brace at every "post to tie-beam" connection would be wise...since the the wind will push the roof and the sidewall will "hinge" at the outer sidewall post/tie-beam joint. Think of the roof being on stilts...you will have to protect the "legs".
And even though your floor joist math works for load...how does it work for floor installation...are you going to have to custom cut each piece?...also is it 2" t&G? or 1x with finished wood flooring? Plywood sub with finished flloor? Having the joists closer together helps support the flooring material so that it doesn't flex too much from one joist to the other.
It's also possible to undercut the bottom of the posts to allow the flooring to pass under the outer edge of the post...like a wrapped dado.
Rooster
Rooster,
Thanks for the input:
On the bracing - what about the two foot extension on the outside posts above the tie beam? No bracing needed (because of the principal purlin - mid-purlin)?
On the flooring - yes, single layer of 2x T&G. My house has floor joists (4x) 48" OC with 1-1/8" ply. I figured the 2x would be good to 36"OC but would be ok doing 24" and recalc the joist size.
For the perimeter - I figured I would need to do some floor trim anyhow so I will just butt to the walls and posts and not worry about undercutting.
f
(https://forestryforum.com/gallery/albums/userpics/17998/DIYTF_QPC_ISO.jpg)
Here is a similar design. I think Clark Bremer has buildt this one a few times for clients.
ljohnsaw,
For Sketchup, you might consider downloading timber frame rubies. You will need this when it is time to make your shop drawing. This add on will let you draw a tenon and then the tenon cuts the mortise in the program. Finally, you use the T F rubies to produce a shop drawing of each piece.
Layers are not needed for the timber frame portion of the drawing. I don't use them at all.
Thinking ahead to shop drawings, you want to keep the components to the stick level. For example 1 tie beam = 1 component. 1 king post = 1 component. You don't want to make a component out of the whole truss.
(https://forestryforum.com/gallery/albums/userpics/17998/ff_xray.jpg)
Look at the tenons on the tie on this x-ray view. The tie beam is a rectangle with tenons but no mortise in it.
(https://forestryforum.com/gallery/albums/userpics/17998/ff_tie.jpg)
However, when I make a shop drawing with TF Rubies, all the mortises appear in the piece. Then use the measure tool and snap on your measurements (I added a few so you can see).
Shortcuts are defined under preferences, figure out what they are and use them. You can also define your own. I've attached the list of standard Sketchup shortcuts.
A standard shortcut is the m-key for move. If you hit m, you will see the move icon.
For the operation you described above. Hit the m key. You will see the move Icon. Select a component. Hit the control key. A plus sign will appear making a copy of the component. Move the cursor back on the component and move it to where you want the new one. Many variations on this, you can move the component a specified distance or you can make multiple copies of the component and specify how far apart you want the copies. Etc. Etc. Etc.
Check out this video:
http://www.youtube.com/watch?v=Yk6ok7S8goA
I can't live without this technique for rafters, joists, etc. It is also used to replicate bents once you have them like you want them.
Another shortcut that is needed all the time. If you have a mouse with a scroll wheel. Push down on the scroll wheel, you get the ability to rotate the work. Push down the scroll wheel and hold the shift, you can pan the work.
Jander3,
Thanks for the tips. I have already downloaded TF Rubies but have not tried making the joints yet. I need to get the basic cabin design down first.
I built up components because the tutorial said you should when you plan to copy large groups. I built my bents as components and then replicated them. However, seeing how TFRubies is to be used to make the joints, I think I painted myself into a corner ::) I've got a lot of work ahead breaking them down.
I've forced myself to start using the shortcuts and they sure save time and I will review your list.
Thanks,
OK, this is officially becoming an obsession!
Here is my latest drawing, complete with all braces, floor joists (2x10s 24"OC) and flooring (2x8 T&G for ease of drawing but will likely be random widths). The only thing missing is the interior walls for the two bedrooms and bath. Turn on the Layers Tool and start subtracting layers to see the details.
Lots of bracing - enough or too much?
The center three posts will be carrying (at least rated for) 20,000 lbs as necessary to carry the dead, live and snow loads.
Open to all suggestions, comments and criticisms.
Thanks all, I couldn't have gotten this far without all of you.
Here is another theme to follow:
http://www.timelesstimberworks.com/luikartcabin.html
http://www.timelesstimberworks.com/horsebarn.html
http://www.timelesstimberworks.com/butternuthollow.html
see attached as a starting point
Quote from: ljohnsaw on February 05, 2013, 02:40:30 AM
OK, this is officially becoming an obsession!
Open to all suggestions, comments and criticisms.
Thanks all, I couldn't have gotten this far without all of you.
Well, congratulations on your newly developed "vice"!! 8)
Here's my list of suggestions:
~Adding more diagonal bracing in the three interior bents from the posts to the underside of the tie-beam.
~Changing the beams down the center of the first floor support system to a continuous/spliced beam with posts below supporting the load and the upper interior bent post resting on top of this same continuous beam. It is easier to keep the beam at a certain elevation and then it will be easier to pre-assemble and raise the interior bents.
~Change the second floor loft joists to beams not planks. You have all of these large structural members that make up the exposed frame and then you have what look like more modern floor joists...could you go to a 6x6 or something that would blend in with the rest of the frame?
~Push the loft floor joist closer to the outer side wall to support the floor near the wall.
~Cut birdmouths on the underside of the rafters so that the fasteners or not the only thing keeping the rafters from sliding down and off the ridge/purlins/top-plates.
~You may want to add additional (long) diagonals just on the endwalls from the purlin post to the top of the tie-beam to give you an additional nailer for the outer sheathing unless you are using SIPs.
~Any sidewall or endwall girts? Doorway?
This should be a fun build for you!!! ;)
Good luck,
Rooster
Rooster,
Interior braces - yep, missed them, got tired last night.
Main floor beam - I was thing of assembling as pieces rather than bents, easier to handle with a small crew (1 to 4)? I could still do a continuous beam.
Second floor beams - agreed. A design question, should the flooring (and the floor beams) be rotated to align with the first floor?
Loft floor joist at end wall - yes, I will be adding girts to nail up the wall boards from the outside (wrap and strap). Doors and windows to be framed as well.
Rafter birds mouths - yes, saving that for when I redo the entire drawing. Birds mouths at the bottom and middle beams but not the top?
Long end wall diagonal - yes, need something for nailing.
Thanks!
l
Jay,
Thanks but I don't have Adobe Flash or SketchUp on my Blackberry so I'll look tonight.
Ok,
Now some design quesions:
My posts and purlins will have braces (36x36) on an 8" face. Size them at 3x5? I will also have some posts to beams braced on a 10" face. Keep the same size brace or go up to 4x6 or so? I will also have some 48x48 braces - go bigger than 3x5?
On my girts, what is the typical size, 3x5? They will not be supporting any load but will be 12' long.
That's it for now, thanks!
Hi Ijohnsaw,
If you are sticking with oblique bracing, instead of horizontal, for a frame your size 4" x 6" is probably better and at 53° 37° 90° (3-4-5 triangle.)
I see almost entirely 45 deg. 36in x 36in 4x4s...95%!!
Rooster
Hi Rooster,
I agree completely, in barns, 45°, is the most common, (not always,) but the size is regional. In these parts the range from 3" x 4" all the way up to 4" x 6", occasionally you will find square stock braces. I know in Illinois I would see 4" x 4" and even 3.5"x 3.5", in some areas.
With Ijohnsaw's frame, with the physical and aesthetic weight of the frame, in addition to the design, I believe a 3-4-5 brace and heavier timber will serve the frame better than lighter timber bracing at 45°. Just a thought.
Regards,
jay
I agree, Brother!
Rooster
Quote from: Jay C. White Cloud on February 06, 2013, 08:12:37 PM
If you are sticking with oblique bracing, instead of horizontal, for a frame your size 4" x 6" is probably better and at 53° 37° 90° (3-4-5 triangle.)
Jay,
The 3x5 size I was getting from the Sobon books but I was thinking that is a little light, aesthetically - I'll go to 4x6. I needing about 80 braces!!! I will be setting up a jig to do those, that's for sure! I'm assuming that the 3' it the horizontal and the 4' the vertical so there is better head room near the braces. I don't understand your phrase "instead of horizontal" - please explain...
Thanks,
Hi Ijohnsaw,
QuoteI don't understand your phrase "instead of horizontal" - please explain...
Did you look and my links and my attachment from post #57 I wrote on 5 Feb. It is nothing but horizontal bracing. I don't use oblique bracing except in historical restoration, when it is original to the frame, otherwise the frames I design are all in the styles that use horizontal bracing, (or you could call it stiffening method.)
Regards,
jay
OK, I see what you mean now. I think that would be a very hard sell to the building department/engineers around here. I have never seen something like that - quite beautiful, though.
So I'm still plugging away with my plan. I just re-drew (most of) it. I did some detail on the foundation and created all the parts as individual components so TF Rubies can process them.
I've set the rafters up with seats now - whats the rule-of-thumb for the amount to remove for the bird's mouth?
Next up is to redo the braces.
Hey,
Since you are re-drawing the structure, have you thought about doing half-lap joints where the upper tie-beam (that connects the purlin posts, or as some call it "Queen Posts"), intersects the posts that support the ridge? This would save a few mortise and tenon joints that you wouldn't have to cut.
Just a thought.
Rooster
Rooster,
Would/could I do a 2 or 3" let in to all three posts (center and queens) so there ar no mortices all the way across? The only difficulty is in the middle three bents, the ties were going to step down to 8x8s from the post sizes of 8x10.
If you are redrawing the frame, I would take some time and figure out rubies. Or, you will have to touch all your components again to put the joints on them. Or just accept that you are going to draw this thing one more time.
For example...put together a bent with all the joints. Once you have it right, copy and place the bent in your frame. On the other end you probably have to rotate it 180 degrees so you reference faces are where you want them. That when you make subsequent changes to one component the change will be applied to all bents. As you get closer to completion, you start to make componts unique so you can put specific features in a bent. And, for the others some will need to be unique when you paint the reference faces.
Timber frame rubies also has a Stretch tool (not in sketchup) that really speeds up the process. And, there is a tool for placing your peg holes.
Hi Ijohnsaw,
QuoteI think that would be a very hard sell to the building department/engineers around here.
Built like this all around the globe, still the most common type, (world wide that is.) Stiffing a frame can be achieved in many different ways. Oblique bracing can be too stiff and that is why it did not take in Asian architecture. Those braces actually, during heaving wind and seismic events act like fulcrums and tear the joinery apart, unless the braces are much farther from the joint than you see in most modern North American frames.
We are years behind in design and configuration application, both in historical and modern design. Many of the modern Northern and Eastern European cutting edge designers/architects are no long employing oblique bracing in the frame itself. Which brings us to the point that most frames don't stand alone, they are covered in a roof and wall diaphragm, whether it is infill, partial infill, or a complete overlay, that will add all the stiffness a frame would need by itself.
Now back to your frame. If you are going to go with oblique bracing instead of horizontals, they need to be further away from the joint than 3' and/or use a 3/4/5 configuration. I would use 4" x 6" minimum. I would also get rid of the long
King Post and transfer that load to a
Cross Tie Beam that is
Lap Jointed in the two
Queen Rafter Tie Plates, freeing up space on the second floor. I would also add a
Broken Tie Beams that lap into the top of the
Wall Rafter Plate and is attached to the
Queen Post with
Wedged Through Tenon both at the gable ends and the center bent.
By the way this last drawing you attached looks good just the way it is, (minus the long King Post.) Add a few interior "stiffening walls," add exterior wall and roof diaphragm, and you would be set. Clean, and open design demonstrating the KIS principle.
Regards, jay
Quote from: Jay C. White Cloud on February 07, 2013, 11:08:08 AM
<<snip>>
Now back you your frame. If you are going to go with oblique bracing instead of horizontals, they need to be further away from the joint than 3' and/or use a 3/4/5 configuration. I would use 4" x 6" minimum. I would also get rid of the long King Post and transfer that load to a Cross Tie Beam that is Lap Jointed in the two Queen Rafter Tie Plates, freeing up space on the second floor. I would also add a Broken Tie Beams that lap into the top of the Wall Rafter Plate and is attached to the Queen Post with Wedged Through Tenon both at the gable ends and the center bent.
By the way this last drawing you attached looks good just the way it is, (minus the long King Post.) Add a few interior "stiffening walls," add exterior wall and roof diaphragm, and you would be set. Clean, and open design demonstrating the KIS principle.
Regards, jay
Jay,
Thanks. I do plan to up the bracing to 4x6 and do the 3/4/5 angle. I'm having trouble following your description above. Can you do a quick sketch? A picture is worth a 1,000 words, as they say. :P
The designs that your present are wonderful but well beyond my capabilites at this time - this is my first project. I want to complete my project in my lifetime :D My timeline is to get the plans approved very soon so I can put the foundation in when the snow clears (July). Next year summer, raise the frame and enclose. Finish inside over the fall/winter/spring.
Hi John,
tonight when I get in I well send you a bent section to look at and some more info...
jay
Hi John,
The attached is an example of what you requested. I noted a symmetry issue from ridge center to outside edge in your model to the attached model, it is corrected in the attached model. The beams have real joinery attached so you can take things apart and look at them. As far as ease in cutting and designing, line rule is no harder than edge rule, and most of my students tell me it is much easier. I haven't had any one got back to edge rule, as their primary layout method, once they have learned line rule, templating and story pole methods.
Regards, jay
Brother Jay,
There's that Asian influence we have heard so much about!!! ;)
Those tie-beam to top-plate connections are gravity held...correct?
Also, is your definition of edge rule the same as square rule? or different?
(If the answer to this secondary question is longer than "it's the same", feel free to start a new chapter...I mean, "thread". thanks! ;D)
Rooster
Hi Rooster, and John,
John, I though about a few things after Rooster jogged my memory. Lap Joints, particularly House lap joints are in a classification of gravity joint, but it truly is a misnomer. In a seismic or wind event you do not get an exact load on the joint and they cam together even tighter. When even trying to take them apart after many year, (or centuries,) they only come apart one way, any other cams the joint tight. Also know that I just gave you two quick and easy samples of that family of joint from a overworked "brain," that is faltering me in my winter days. There are multiple ways to also lock them together with spline and tenon, one being a version of the "hell joint on a teasel tenon," and with modern timber framing having mechanical and thermal enveloped incorporated into the structure; these exterior joints are further locked and stiffened. Which is also what I was explaining about frame stiffening as well.
Yes Rooster "edge rule," and "square rule," are synonymous with each other and very similar to "mill rule," all relatively new methods, (less than 300 years.) "Scribe rule" is the oldest with a close second being "Line rule," those two have been around for almost 3000 to 5000 years, depending on the literature/research sited.
/
Till later my friends,
jay
Ok, Jay,
I won't say I gave up, but I tried your 3/4/5 and re-drew the rafter and braces. Take a look. I will admit that it is more pleasing to the eye. ::) On the west end above the door, there will be two big windows on the second floor. On the left half of the bent will be a big window or two. Between the girts placed at 3'6" and 7' will be a window in every bay.
I did NOT recalculate the rafters and beams I may be able to downsize but probably not much. I have yet to design the second floor joists so they "fit" with the other timber sizes. The first floor will remain dimensional lumber since it will only be visible from the basement. That's all for tonight!
Hi John,
In short, I think you have found the style that fits you. :) You seem to have found a theme I would describe as contemporary, "Germanic-Eastern European." At this point of the exchange I think I shall fall silent, and be just an observer. I can not really give anymore design advice that I think you would find useful, that I haven't already shared. The frame is so over built that I can't imagine any PE with, or without, timber framing experience having much difficulty with the frame, so you should have not difficulty getting the design approved from a structural integrity perspective.
I thought you would be happy with the 3-4-5 theme component and you took that to heart. I really do like the overall shape and layout of the frame. In closing, if I was to critique the frame it would be as follows:
Roof pitch excellent in all regard: traditional theme, roofing longevity, percipient shedding and head room for second floor.
From the Gable end with the cathedral ceiling, I would replace the Gable and the next two bents in with a "Cruck Frames," as there is no need for all the other work as there is not second floor in that location. In addition, it would add statement to the theme of the building with out adding work or cost.
It you are going to have this many braces you do not need to design wall purlins into the timber frame system, they will come naturally with whatever mechanical/thermal envelope system you choose. That additional timber framing only adds cost and work. The opposite is true in my design system, I use the purlins to stiffen the frame, having no obliques, and any additional rigidity that is required by PE is contained in the mechanical/thermal envelope of roof and wall diaphragms.
In closing, I think you are doing well in finding your "voice," design wise.
Good Luck, ;D ;)
jay
Jay,
Thank you for your pesistence in opening my eyes.
In regard to the open frame in the front portion: I may mess around with that a bit. As drawn, I can easily add more second floor area if I choose to in the future. I like the feel of big timbers so I'm not oppressed by their presence. But I will explore more.
In regard to the wall purlins (girts): they are present for two reasons, a place to anchor the 1x wall boards (wrap and strap) and to frame out the windows. If there is a simpler, faster way, I'm all ears.
Jim has been strangely silent, I hope all is well. Perhaps he is just letting you express yourself.
OK, for all you SketchUp users - I thought I saw it once but now cannot find it. Where is the Xray toggle? Is it only in the Pro version?? ???
View---Face style---xray
Quote from: Rooster on February 08, 2013, 11:52:50 PM
View---Face style---xray
Thank you! I thought I was going crazy!!!
John:
I haven't taken the time to download your latest version.
I may some time, but kind of busy now.
I spend 24 hours plowing snow the other day as we got 24 or 25 inches here in one storm.
I still don't have all my sawmill yard cleaned up yet.
I spent several hours out there today, pushing it back, scooping it up and hauling it off.
There is always something to do.
Rained today on top of all this snow.
Very heavy now.
Suppose to be 40° to 45°F every day this week, so it should melt a lot of it.
Jim Rogers
Jim,
Good to hear that you are just really busy. Don't download my plans from above. I will be posting a new-and-improved plan shortly, perhaps tonight. I spent a lot of time in x-ray mode clearing up some of the joints where braces were coming in. I think I've master the "component" idea so I can work pretty fast now. I need to do some sections to make sure I have enough wood left in the posts to support the load.
John
OK, here is my latest plan. I've added the flooring and spent quite a bit of time getting some stairs to work. The stair to the basement will be framed out and have a door do seal out the cold. While the upstairs could be turned into bedrooms, I plan on just leaving as a sleeping loft for when we have guests with kids visiting. The extensions on the front foundation are meant to hold beams for the deck. Next I will be framing out the two bedrooms, bath and the kitchen. Comments and suggestions always welcome. To get better views, I've used layers pretty extensively so try turning different things on and off.
John,
Welcome back!
It is really starting to come together! Here are some comments and concerns.
Your stairs are a bit steep...you have almost an 8" rise and only a 8.5" run.
Have you thought about moving the the stairs one more bay closer to the front of the house (towards the end-wall with the door)? This way you could have the top of the stairs end or attach to the second floor tie-beam,...it would run parallel to the front loft area, and you wouldn't have to cut through the upper floor, making a more open area up in the loft.
Could you timber frame the supports for the porch, instead of using concrete?...could be a nice accent and not so monolithic.
I also came up with an alternative to the lowest girts or nailers. If you secured a 2x4 between the outer posts, flush to the outside of frame wall, and then raised the joists to be flush with the top of that 2x4, you could then nail the bottom of your first outer layer of sheathing to that 2x4 instead of the girt. It's an easy change and eliminates a large number of joints to cut. If you really needed to, you could adjust the length of the posts to keep the same tie-beam elevation as before.
Lookin' good!
Rooster
(https://forestryforum.com/gallery/albums/userpics/15824/LJohnSaw2BCabin2B2012-02-13-inline_stairs.jpg)
Rooster,
Great ideas...
Regarding the lower girts: I was thinking of just nailing into the floorboards but that would give me end grain on the bent ends. Your plan also simplifies the floor joists.
Regarding the porch supports: there will be some back fill around the cabin. I'm also looking to keep the snow off the basement entrance. 10' is not an uncommon amount of snow at my location.
Regarding the stairs: they are only 43 degree! I could slide back in the bay a little now that I have repositioned the basement stairs and go with a little lower slope like 40 or 38. I don't want to move into the second bay as that would complicate the kitchen entrance (north of the stairs) and break up the great room. I'll take a look, however.
Thanks
r
Good Looking Frame. So what's the Ponderosa running per bd/ft? Frame looks like about 18,000 bd/ft.
Hi John,
It's look'n good, Dido Roosters observations.
Regards,
Jay
Quote from: swampfox on February 14, 2013, 02:55:44 PM
Good Looking Frame. So what's the Ponderosa running per bd/ft? Frame looks like about 18,000 bd/ft.
Swampfox,
Wow, that is a scarey number! Since I will be harvesting my own trees, it will be free (since my time is free) :D
I plan to use three species of wood (not counting the oak pegs): Beams, posts, joists and rafters will be Ponderosa, wall and roof boards will be incense cedar and flooring will be quaking aspen. I have plenty of each.
I'm guessing I will need somewhere between 300 and 400 pegs. I guess I could fill my time next winter producing them - or do any of you purchase pegs?
I just did a search for California building codes for stairs and this is what I found.
http://www.bertramblondina.com/articles/4-stairbuilding-techniques/42-stair-building-codes
R311.7.4.1 Riser Height. The maximum riser height shall be 7 3/4 inches. The riser shall be measured vertically between leading edges of the adjacent treads. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch.
R311.7.4.2 Tread Depth. The minimum tread depth shall be 10 inches. The tread depth shall be measured horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread's leading edge. The greatest tread depth within any flight of stairs shall not exceed the smallest by more than 3/8 inch.
I try to stay close to 7.5" rise by 10" run...FYI
Also, your flooring will expand and contract with the seasons and the relative humidity. Asking the flooring to pull "double duty" by making it also a "Structural component" may be unwise.
If you have the time...make your own trunnels.
If you have the money, after you get tired of making trunnels...buy your trunnels.
Pullin'for-yah Brother,
Rooster
920-728-zero 3 five 3
Quote from: Rooster on February 14, 2013, 05:36:22 PM
I just did a search for California building codes for stairs and this is what I found.
http://www.bertramblondina.com/articles/4-stairbuilding-techniques/42-stair-building-codes
R311.7.4.1 Riser Height. The maximum riser height shall be 7 3/4 inches. The riser shall be measured vertically between leading edges of the adjacent treads. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch.
R311.7.4.2 Tread Depth. The minimum tread depth shall be 10 inches. The tread depth shall be measured horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread's leading edge. The greatest tread depth within any flight of stairs shall not exceed the smallest by more than 3/8 inch.
I try to stay close to 7.5" rise by 10" run...FYI
Roger Rooster... ;)
Quote from: Rooster on February 14, 2013, 05:36:22 PM
Also, your flooring will expand and contract with the seasons and the relative humidity. Asking the flooring to pull "double duty" by making it also a "Structural component" may be unwise.
Yeah, I kinda figured that so I didn't do it.
Quote from: Rooster on February 14, 2013, 05:36:22 PM
If you have the time...make your own trunnels.
If you have the money, after you get tired of making trunnels...buy your trunnels.
Pullin'for-yah Brother,
Rooster
920-728-zero 3 five 3
OK, trunnels, not pegs, though my spell checker doesn't like it! Obviously, the best way to make them is to split wood so the grain is not compromised with cutting on a table saw or such. I think I read here that making them octagonal is really about all you need to do besides giving them a slight taper to get them in the hole. Sound right? As far as buying, I saw some for about 50 cents a piece - that can add up!!! If I value my time, I'm sure I could get my price all the way down to $1.00!
Thanks all. Back to SketchUp!
Hey John,
Peg or Trunnel we won't gig you for it. FYU furniture is pegged, timber frames get trunnels, but language changes and there are different names in different culture. Rooster's advice is very sound on all points, nothing to really add. Having made many trunnels and pegs in my life, it can be laborious work.
Now for round, octagonal or even round w/square ends, the strength of riven grain is true, and good manufactures of trunnels for timber frames know this. Now one issue I have noted in recent years is they have begun using kiln dried wood. If you are going to "draw bore," your joints they will need to be soaked in oil or water, I've seen both. The trunnel needs to be somewhat supple, there by "bending," slightly as it draws the joint tight. You will also need "draw pins," to do the job well. By the way, it isn't a scientific test or proof, not by any means, but we always test out ideas, and on several occasions over the years we have set up trials to compare the two-"riven," or "sawn." The difference, as long as you used straight grained wood, was none to marginal between the two. Also use a striking cap over the trunnel as you drive them in, this can save you from miss hits, deformations, broken trunnels for glanced blows, or even dents in your frame because you have enlarge your target. I use steel 3 lb sledge on both my chisels and my trunnels, but I have been told I can be a beast. ;) :D :D
Keep us up to speed.
jay
I like to make my own pegs using a shaving horse; however, I am not into timber framing for production. I cut 1" x 1" lumber on the saw mill, cut them down to pieces that are about 12" long, and then throw them in a tub of water to soak for a day or two.
It takes a couple of minutes with a shaving horse to make an 8-sided tapered peg for drawboring. At my place, peg making is normally done in the evening and it is closely associated with shooting the bull with friends and a beer or two.
(https://forestryforum.com/gallery/albums/userpics/17998/3171/DSC02363.JPG)
Shaving horse...the seat is way too short for a tall guy, but that is what was around when I made this up.
Quote from: jander3 on February 15, 2013, 11:53:50 AM
I<<Snip>>
Shaving horse...the seat is way too short for a tall guy, but that is what was around when I made this up.
Nice. Actually another one on my to-do list along with the mare and colt.
A little more work completed. Spent a lot of time in x-ray mode adjusting joint positions. Finished the stairs, raised the first floor 2" to make room for the perimeter 2x4 nailing sill, added walls for the bedrooms with closets (need to add the bath and kitchen) and added wall boards (need trimming) and roof boards. And need windows! See attached.
Comments welcome!
(https://forestryforum.com/gallery/albums/userpics/30640/LJohnSaw2BCabin2B2012-02-16-inline_stairs.png)
Ops! I saw the problem with the upper floor cut out not being big enough for the stairs - ignore that minor error!
John,
It looks like you are setting yourself up for success!!
Here are a few problem areas:
The interior post diagonal at the bottom of the first-to-second floor stair case is in the way...when your wife cracks her noggin on it coming down the stairs you will feel her pain...haha
The second floor joists on either side of the stair case stringers are too close...Your stairs seem to be legal, but the floor opening may not be...could you push them to outside the stringers?
(https://forestryforum.com/gallery/albums/userpics/15824/LJohnSaw2BCabin2B2012-02-16-inline_stairs01.jpg)
The first floor joists that dead-end into the stairwell opening in the first floor are secured to a beam...this beam is attached to a doubled up joist on one side, but only a single on the other side...you would be asking that single joist to carry half of that section of floor.
(https://forestryforum.com/gallery/albums/userpics/15824/LJohnSaw2BCabin2B2012-02-16-inline_stairs02.jpg)
The posts that frame out the front door look like they were cut off...could you extend them up to the tie-beam, wrapping around the lintel (top of the door frame)? You could also put in a transom light/window above the door...eh? Any other endwall girts?
(https://forestryforum.com/gallery/albums/userpics/15824/LJohnSaw2BCabin2B2012-02-16-inline_stairs04.jpg)
The cut-out for the "garage" door in the foundation under the deck does not leave a lot of concrete above that door. I am afraid, especially in "quake country" that it will eventually crack. Could you replace it with a steel I-beam or even another wood beam that can be covered and protected from the weather?
(https://forestryforum.com/gallery/albums/userpics/15824/LJohnSaw2BCabin2B2012-02-16-inline_stairs03.jpg)
Well I hope i didn't beat you up too bad...lots of guys here who wish they could be doing what you are...myself included.
Rooster
Looking great!
Looks like all the tenons on the post are cut with an offset of 3". Normally, a tenon would be laid out 2" (tongue size on square) from the reference face. The tenon would end be offset, but that works fined.
The layout for the King posts and ridge are done from the timber centerline. In that case you probably want the tenon centered.
Girt tenons are on the outside of the building. Where you just going to nail these in. You can put the tenon on the inside and slip them in during assembly like you do for a knee brace.
I would drop some of the Knee braces in the open areas inside the building.
Knee braces with girts on the building end looks problematic. As you when you cut this you will not have two reference faces. I would drop that upper girt and move the braces to the outside (reference face) of the building.
Quote from: Rooster on February 16, 2013, 01:45:29 PM
John,
It looks like you are setting yourself up for success!!
Here are a few problem areas:
The interior post diagonal at the bottom of the first-to-second floor stair case is in the way...when your wife cracks her noggin on it coming down the stairs you will feel her pain...haha
Ops! Well, it would just be me cracking my noggin! I lost my wife 3 years ago now. My son won't be hitting that for a number of years and my daughter is short enough that she would miss it!
Can I just eliminate that brace? ??? Should I reverse the measurements (3/4/5 to a 4/3/5)?
Quote from: Rooster on February 16, 2013, 01:45:29 PM
The second floor joists on either side of the stair case stringers are too close...Your stairs seem to be legal, but the floor opening may not be...could you push them to outside the stringers?
I'll need to check on the opening. I think the stairs are wide enough - this is a "non-living" area - just a sleeping loft. Technically, I could get away with a ship's ladder!
Quote from: Rooster on February 16, 2013, 01:45:29 PM
The first floor joists that dead-end into the stairwell opening in the first floor are secured to a beam...this beam is attached to a doubled up joist on one side, but only a single on the other side...you would be asking that single joist to carry half of that section of floor.
Thanks, missed that one. I still need to engineer the joist/beam to carry that load.
Quote from: Rooster on February 16, 2013, 01:45:29 PM
The posts that frame out the front door look like they were cut off...could you extend them up to the tie-beam, wrapping around the lintel (top of the door frame)? You could also put in a transom light/window above the door...eh? Any other endwall girts?
Nice thought - I'll give it a go. The other opening will be some large fixed windows, probably a pair of 4' sliding door panels.
Quote from: Rooster on February 16, 2013, 01:45:29 PM
The cut-out for the "garage" door in the foundation under the deck does not leave a lot of concrete above that door. I am afraid, especially in "quake country" that it will eventually crack. Could you replace it with a steel I-beam or even another wood beam that can be covered and protected from the weather?
I haven't visited that area in a while. It started out as a 2' beam. I'm looking into Faswall block and it would end up with two reinforced concrete 4.5x4.5 "beams" in the blocks. There will be VERY little weight on these and full of re-bar!
Quote from: Rooster on February 16, 2013, 01:45:29 PM
Well I hope i didn't beat you up too bad...lots of guys here who wish they could be doing what you are...myself included.
Rooster
Thanks for the pointers/ideas.
Quote from: jander3 on February 16, 2013, 02:06:36 PM
Looking great!
Looks like all the tenons on the post are cut with an offset of 3". Normally, a tenon would be laid out 2" (tongue size on square) from the reference face. The tenon would end be offset, but that works fined.
Yeah, been messing with that. Originally, there was too much going on in the joints and centering fixed it. I'll be using a Big Al (homemade) so the offsets would not be an issue, whatever they end up being.
Quote from: jander3 on February 16, 2013, 02:06:36 PM
The layout for the King posts and ridge are done from the timber centerline. In that case you probably want the tenon centered.
Girt tenons are on the outside of the building. Where you just going to nail these in. You can put the tenon on the inside and slip them in during assembly like you do for a knee brace.
I figured I'd have enough to do without worrying about those as well. I'll just nail them in, they will be hidden anyway. They are not structural, just a nailing point for the wall boards and a "sill" for the windows.
Quote from: jander3 on February 16, 2013, 02:06:36 PM
I would drop some of the Knee braces in the open areas inside the building.
On the first floor, right? That will make for lots of bracing!
Quote from: jander3 on February 16, 2013, 02:06:36 PM
Knee braces with girts on the building end looks problematic. As you when you cut this you will not have two reference faces. I would drop that upper girt and move the braces to the outside (reference face) of the building.
The upper girt is a reference for the top of the windows. Not sure I want to lower them. As for the reference faces, I am "assuming" that on the first 4 bents, the reference edge is the west outside corner. That is, the west face and the other face toward the outside of the building (north side - north, south side - south). The extreme east bent (#5) would be working off the east face.
So the tie beams housing would be measured of the north or south faces, not the inside faces, correct? The girts housings on the long walls (north and south side) would be referenced from the west (except #5) face. So, I being a novice, don't see a problem in setting the braces back from the face to make room for the girts.
PLEASE, enlighten me if I've made an impossible design!!!
John,
I would eliminate the diagonal near the stairs. Even though all the wind-bracing makes up the system, removing one won't be the end of the world.
Will there be any inspection on this building? Not worried about codes?
I also forgot to mention that the first step up from the basement is a bit tall...kind of like the old saying,"That first step is a doozie!"
Rooster
Quote from: Rooster on February 16, 2013, 02:58:00 PM
John,
I would eliminate the diagonal near the stairs. Even though all the wind-bracing makes up the system, removing one won't be the end of the world.
Will there be any inspection on this building? Not worried about codes?
I also forgot to mention that the first step up from the basement is a bit tall...kind of like the old saying,"That first step is a doozie!"
Rooster
OK, removed the one brace, added a bunch of knee braces along the long walls. Didn't think they would be necessary on the short walls with all the other bracing going on.
Fixed the stairs, doubled up the floor joist but still need to calc it. Adjusted the front door opening and attached it to the tie beam.
Yes, I will be having it engineered and inspected. Too close to civilization...
John,
I see that you doubled up that floor joist...you would only need to double it up from the sidewall foundation to the top of the center load beam...not the entire width of the building.
And revisiting the second floor opening for your stairway... your stairs are probably wide enough for code, but the reduced size of the opening, which you have at 31", is probably not. I am not a code expert, I only want you to be sure before you take your plans to an engineer...less headaches down the road.
Is it possible to narrow the distance between the stringers from 41" to 36", spread the distance between the upper floor joists from 31" to outside the stringers at 44"? I know that you have the joists spaced at 36" o.c., but I think that it would look better.
Rooster
PS Now all you need is a carved wooden Viking dragon along the ridge line... ;)
Quote from: Rooster on February 16, 2013, 07:59:46 PM
John,
I see that you doubled up that floor joist...you would only need to double it up from the sidewall foundation to the top of the center load beam...not the entire width of the building.
And revisiting the second floor opening for your stairway... your stairs are probably wide enough for code, but the reduced size of the opening, which you have at 31", is probably not. I am not a code expert, I only want you to be sure before you take your plans to an engineer...less headaches down the road.
Is it possible to narrow the distance between the stringers from 41" to 36", spread the distance between the upper floor joists from 31" to outside the stringers at 44"? I know that you have the joists spaced at 36" o.c., but I think that it would look better.
Rooster
PS Now all you need is a carved wooden Viking dragon along the ridge line... ;)
Rooster,
I just re-read you note about the tread width and modifying the floor joists - it now makes sense to me. I'll have to give that a try.
In the meantime...
I was adjusting the structure (the foundation) to be 6" shorter so I end up at an even foot mark - makes the use of Faswall blocks much easier. Somehow, I blew away my whole foundation. But, that was actually good news. I originally started with the foundation and didn't really understand the concept of Components. I made the entire foundation a thing and editing it was a bear. I now have three components - the footing, the walls and the slab.
So I've added what I think will be the bathroom space. The bump out will be the shower. It gives a little mini-hallway that I will probably make into a linen closet on one end and a pantry for the kitchen in the other end.
So, what to do about the braces inside the living space? I put up some guide lines at 6' 8". The braces project out into the living space about 20" at that height. Is that a problem, should I down-size those braces? Put some furniture or a plant there so no one will walk there? Should I make them curved? If I do, do I need to make all of them curved for aesthetic reasons? In all, there are 7 to consider (one removed at the staircase).
Quote from: ljohnsaw on February 17, 2013, 09:08:11 PM
Rooster,
So, what to do about the braces inside the living space? I put up some guide lines at 6' 8". The braces project out into the living space about 20" at that height. Is that a problem, should I down-size those braces? Put some furniture or a plant there so no one will walk there? Should I make them curved? If I do, do I need to make all of them curved for aesthetic reasons? In all, there are 7 to consider (one removed at the staircase).
I went and placed a "carpenter" who stands about 5'9" into your frame near an interior diagonal. I did not alter the last drawing that you uploaded.
My suggestion would be to add the equivalent of at least one step to the bottom of all the posts (~7.5", which will make the additional step easier to add) this will raise the tie-beam and diagonal heights, making it easier to pass by a post without bumping your head. It will also make the rooms feel larger and make it easier to add ceiling fans with the added height. You could make the diagonals smaller, but I like the size for your wind-load.
Rooster
(https://forestryforum.com/gallery/albums/userpics/15824/LJohnSaw2BCabin2B2012-02-17-inline_stairs_28129carpenter.jpg)
Rooster,
I don't know what I was thinking - maybe the stair clearance of 6' 8". Though, that is a short carpenter! I went through and "finished" the kitchen, adjusted the stair width (code says must be min 36" clear tread), downsized the stringers to 3" thick, spaced the second floor joists at 48" OC. I also raised the second floor by 7.5" to move up the braces. At 6', you have to be within 8" of the braces to smack your head. I'm good with that.
Hey! Watch who you're callin' short! bat_smailey haha
I like the second floor joists on the outside of the stair stringers...but I would go back to your previous joist spacing, tuck the stairwell as close to the interior post as you can (you can utilize the post for handrails and you could also add another post, on the other side, at the bottom of the stairs for the other handrail), and don't worry about being completely symmetrical with your joist layout... think of the staircase and it's two corresponding joists as a separate unit that you are placing where you need, that is not in line or o.c. with other joists. Try it,... Function will prevail over Pretty.
Also, all of the interior door lintels and your door lintel/upper girt on the end-wall could be brought down to frame the top of the door openings.
Good Job,
Rooster
OK, one more time...
I've reduced the foundation to an odd foot mark to make the Faswall block system work without cutting or using "1/2" blocks (1'x1'). Now the foundation is 51'x25' and the inside of the plank walls / outside of the timbers is 50'-4"x24'-4".
I've re-aligned the stairs to the center post, "built out" the kitchen and bath. Not sure of the space used by the shower - might reduce that to make room for a linen closest/pantry closet between the shower wall and the stairs.
I lowered the interior door lintels to 6' 10" (I think) to frame out a 6'8" or so door (custom made by me). I raised the girts for the windows. I put in 2"x11" planks to make the box for the 3'x4' windows. The girts (4") + 1" of board, 5" of rigid insulation and a 1" cleat to attach the concrete lap siding. Between the cleats, another inch of rigid foam.
Comments please!
Here's my short list:
You have the first floor flooring running out past the outside of the outer posts.
Interior walls sticking out past frame?
You might need a couple short posts at the bottom of the first floor stair landing for handrails and so that it's not a trip hazard traveling in and out of the kitchen area,
The walkway between the stairs and the breakfast bar is a bit narrow.
The guardrail at the top of the second floor landing needs to be updated.
Lower girts on either side of the front door???
Fireplace? lol
Keep on Keepin' on!!
Rooster
Quote from: Rooster on February 21, 2013, 07:48:42 AM
Here's my short list:
You have the first floor flooring running out past the outside of the outer posts.
Interior walls sticking out past frame?
You might need a couple short posts at the bottom of the first floor stair landing for handrails and so that it's not a trip hazard traveling in and out of the kitchen area,
The walkway between the stairs and the breakfast bar is a bit narrow.
The guardrail at the top of the second floor landing needs to be updated.
Lower girts on either side of the front door???
Fireplace? lol
Keep on Keepin' on!!
Rooster
Well, crud - I posted the wrong file!! This was an incremental save. I'll try to get the right one posted tonight. As for a fireplace, that funny little pad in front of the second bent is a hearth for a wood stove.
John,
You wound a little tight about this project? Are you getting enough sleep without dreaming about this frame? :D :D :D
You'll get there!!
Rooster
Ha Ha... I typically work on it from about 8:30 until midnight and then think about it for an hour or two when I go to bed! I want to get this ready so I can break ground this summer. However, I first must get a producing well installed on my property as well as some septic system. So, I want to have my plans approved by an engineer so the County will accept them. Lots to do and the warm spell we are having now is giving me spring fever!
Stay tuned!
OK, try this one! My son told me to fix the year!!!
Ok...Let's fire up the mill!!!
I'm with Roster, your there my friend. Maybe, since you are going the oblique brace way and are in California, you should just add a few buttress braces on the first floor at the Gable ends, otherwise start milling!!! 8)
Regards,
jay
Quote from: Jay C. White Cloud on February 21, 2013, 09:40:32 PM
I'm with Roster, your there my friend. Maybe, since you are going the oblique brace way and are in California, you should just add a few buttress braces on the first floor at the Gable ends, otherwise start milling!!! 8)
Regards,
jay
Are you saying that because of earth quakes? I'm too far away for anything major. Though it wouldn't hurt!
Would you do just the corner posts or the middle post as well?
Hi John,
Well actually, of the oblique braces, the ones that emulate nature, (like at the base of a tree,) are then ones that really work the best. you can get away without them in the living area, but the gables wouldn't hurt. Matter of fact, most frames that have oblique braces, would benefit more from them at the base of a member, then up high on the post.
Now remember, I saying this as a generalization of where they perform the best. In general, with modern timber framing methods and other regional modalities, as I have already stated much earlier in this post thread, you could take most of the oblique bracing in this frame out and still pass muster.
I like your frame, it speaks to your taste and design since, so don't second guess yourself now. As I had said, I've just been watch'n for the most part, because this is more of the European design them, and I follow Asian metaphors in architecture for myself, that's my taste.
In short, buttress braces won't hurt...NO, you don't have to have them, the wall diaphragm will take care of that.
Get to mill'n as Rooster said. ;)
Quote from: Jay C. White Cloud on February 21, 2013, 11:55:29 PM
Hi John,
<<snip>>
Get to mill'n as Rooster said. ;)
I played with it for a while and added the buttress braces, as you call them, on the end bents. They actually look kind of good there. But only on the center posts.
I trimmed out the wall boards so I can view the inside and really get a feel for how it will look. I like it.
I can't "git a millin'" right now. I have to procure a permit to build - before that, I have to have the plans approved by an engineer. Before that, I need to have a water supply and septic. Soooo, when the weather is cooperating (in about 4-5 months), I will have the well guys out to see if we can find water. At the same time, have an engineer go over my plans. If that all works out - then I build the foundation this summer and construct next summer.
I've got a price on the composite ICF (Faswall) of $7.84/sqft of wall area (outside) so I'm looking at about $14k in block + the concrete to fill (.333 cuft/sqft).
This is gonna be fun! 8)
Final drawing (I hope...). I've completed the skin with rigid foam, battens and hardi-plank walls and sheet metal roof. I sent this off to an engineer for his look-see and to find out if he wants to do the work or someone he knows that does timber frames will take it on.
Next step is septic, then well.
Are you sure this is the final drawing?
Is this the one you sent to the engineer?
Rooster
Quote from: Rooster on February 26, 2013, 07:48:10 AM
Are you sure this is the final drawing?
Is this the one you sent to the engineer?
Rooster
Ummm, I think so and yes... Why, is there a glaring error?
Umm...I'm looking at a frame with window frame-outs...no skin with rigid foam, no battens or hardi-plank walls and no sheet metal roofing...
oops!
Send us a different one...when you have time. ;)
Rooster
I sent it like this becuase I want him to see timbers. Try enabling the "layers" dropdown and turn on all the different components. :)
Boy, you got good at Sketchup. I'm still learn'n how to designate "layers," but turning them on and off is easy, great idea on your part. The PE can really take things apart fast.
Good Job
OK, the concept drawing is off to an engineer to give me a quote to go through it, structurally.
Other to-do's on my list:
1) Go through the hassle of getting the septic installed. Somewhere between $10k and $40k (if needs to be an "engineered" solution).
2) Get a producing well.
If anyone has any experience and can help me avoid a major expense and time delay: In their infinite wisdom, California law-makers (since 2010) have determined that requiring a fire suppression system (aka sprinklers) in ALL new construction (residential included) will help prevent structure fires. Never mind that in the mountains, wildfires are the predominate reason houses burn down!
So this throws a wrench in the works. My plan was to go solar, which I probably still can do. I just need to up my battery storage to drive a significant pump load (when called for) for the sprinklers. That is, unless someone from CA can point me in the direction of a loophole!
Talking with one engineer and my desire to do the timber frame cutting myself - his suggestion was to cut the timbers (slightly oversize) this year and let them dry a bit, finishing the cutting next year. That would, in his opinion, reduce the problems of various shrinkage occurring because I could only cut so many timbers so fast. Sound reasonable?
From what I have gathered from this site, I would cut, sticker and stack with a loose cover to protect from direct sun. When winter comes, completely wrap the stack to keep rain and snow off but somehow allow air flow? Bear in mind that my piles (5 or 6' high?) would be buried under 6 to 8' of snow before the spring. Suggestions/guidance?
How many gallons per minute will you need to push?
How many gallons total?
How many sprinklers?
Hi John,
Timber frames are built with green wood. If you are going to wait to build stack and sticker the whole timbers till you can cut the frame in one push. Joints can distort if cut and stored for a long time, especially using "edge rule", (not so bad with "line rule,"), To get something even as small as a 4"x6" to "dry out" is going to take a couple of years, and forget your big timbers drying, that ain't go'n happen for a long time, so your PE was a little off on that.
Fire suppression systems are required here in Vermont in some townships for new construction as well. That is another reason I like the wall truss system, because you can place you plumbing in them easily. The ceiling is a bit more of a challenge, so I would have to think about it in your case. We build double and triple roof systems accordingly for homes that require fire suppression.
Best of luck,
jay
Quote from: Rooster on March 05, 2013, 12:02:17 AM
How many gallons per minute will you need to push?
How many gallons total?
How many sprinklers?
At this point, I don't know. Waiting for a quote to figure out a design.
Since my floor plan is relatively open, perhaps four (one each bay?) at the peak and one each for the two bedrooms, bath and kitchen (all under the loft area). That gives a total of 8. I'm guessing 1/2 GPM each, so 4GPM (about a full blast garden hose). The PE did mention about 2,000 gallon water requirement to meet code.
One option is to use a "dry" system - there is no water in the sprinkler pipes to freeze when I am away. This drain-back system then could use a single source of water - the domestic tank. I just need to figure out a way to prime the pump when needed. A lot of cabins use a air-pressurized system for the domestic water. It gets really complicated with freezing temperatures...
Quote from: Jay C. White Cloud on March 05, 2013, 12:06:58 AM
Hi John,
Timber frames are built with green wood. If you are going to wait to build stack and sticker the whole timbers till you can cut the frame in one push. Joints can distort if cut and stored for a long time, especially using "edge rule", (not so bad with "line rule,"), To get something even as small as a 4"x6" to "dry out" is going to take a couple of years, and forget your big timbers drying, that ain't go'n happen for a long time, so your PE was a little off on that.
<<snip>>
Best of luck,
jay
The PE was NOT suggesting cutting all the joints as I go along. He was suggesting cutting all the timbers and then the joints. I was planning on doing that in a modified way.
Thinking out loud, I figure I will cut all the small stuff (braces) first since I will have about 200 of those, it seems ::). Then I would cut the large stuff to size followed by the joints.
To start out, I figure I should be able to finish one timber a day (4 to 8 "half-joints" each). At that rate, it would take me about a week to make a bent. I know I should keep my green wood from drying too fast, so my thought is to complete the 5 bents and do the assembly when I have all the roofing system ready to cover it up - right?
So, even before I start on the timbers, I need to have all my floor joists (2x12s and 5x9s), rafters (5x9) and planking (2x's T&G) ready to go. Somewhere in there I will need 2,500 BF of 1x wall boards as well (T&G) as that would go up shortly after the roof.
My mistake ;D Yes much better now I understand your strategy. ;)
Now lets wait and see what the PE has to say about the frame?
Quote from: Jay C. White Cloud on March 05, 2013, 07:40:40 AM
Now lets wait and see what the PE has to say about the frame?
Well the (first) engineer had a lot to say.
#1, the "wind bracing" will not even come close to meeting the (California) seismic requirements. Either cover the entire structure in plywood/osb or have some diagonal steel rods in various places. I'd rather do the steel (visible) than the ply - a sort of industrial look.
#2, I need to have a plywood sub-floor to meet seismic, even though it is pretty much directly attached to the reinforced concrete foundation!
#3, thanks to a new (2010) building code, I need to have a sprinkler fire suppression system installed!!! Fortunately, I have a friend in the business that will work with me and do it at cost (~$1,300 instead of $3-6k).
I'm planning on getting two more opinions before I plunk down the money ($10-15k) for the actual work.
Seems that the state-wide seismic code is designed for L.A. or San Francisco, not the high sierras with no earthquakes!
Also, I was visiting my property on Sunday. I will have to rotate my building 90° due to the limited level building spot. Now my deck will be on the south side - not so much an issue - but my roof slopes will be facing east/west messing up my solar setup. Though, I don't need too many panels - maybe have them on the front of the building where I have some blank wall space. They could even be "awnings" over the windows... hmmm
Hey John,
I believe that is what he told you, I even believe he believes it. However, I think you need to peel a few more layers of the onion back. That frame, design they way you have it, is way stronger than most stick built structures with their ply wood skin. I think he is out of his league as a timber frame is concerned and doesn't really know, understand or trust the legitimacy of the architecture. It is common for us to meet this type of opposition from PE that are not familiar with timber wrights.
I'll share a little story with you, for what it is worth, and maybe you can approach the PE again. I was part of a project near Paso Robles, CA. We got the same reaction. So the entire frame got covered (the wall and roof diaphragms) with two layers of 1" board. The boards did not go to the sill, so there would be access to a wiring chase. Then a grid of strategically spaced Kevlar strapping was placed at oblique angles over the frame, staying clear of the projected fenestration of the frame. It was simple to apply and work with. When the PE was approached with this solution he still did not want to concede his original solution, (similar to your PE solutions.) That was until we pointed out that his own firm was using this method on commercial condos in LA with "stick framing." There is always another solution, and often it is better than what you are offered.
Have you tried:
http://blog.ftet.biz/
Ask for Ben and say I sent you. He knows timber frames, if he comes to the same conclusion as your current PE, I would except it. He can think outside the box and always has alternative solutions.
Regards,
jay
Firetower is one of the engineers I use, as well.
Jim Rogers
Jay & Jim,
Thanks. I'll check them out. I'm in contact with a free-lance engineer who should have time to view my work in a few days. My company used him on some commercial remodel work and I found him to be very knowledgeable and agreeable. He was alway accepting of my ideas.
Jay/Jim,
I had a quick series of emails with Ben at Fire Tower. What a great guy. He gave me some additional ideas and some questions to run down with my county. We Skyped (my first time) so we could real-time discuss the issues. Unfortunately, my county will not answer my emails (it seems). I was hoping to get a written trail of their "OKs" to my questions.
The best idea I got from Ben was to use something like Simpson straps on the outside of my braces to provide the necessary seismic strength (tension) while the braces (slightly repositioned as seen below) provide the compression strength. That way, #1, I don't have to plywood the walls and #2, they are completely hidden.
(https://forestryforum.com/gallery/albums/userpics/30640/LJohnSaw2BCabin2B2013-03-21-25x51.jpg)
Yes, if you look closely, those are some deep dado cuts in the sills for the straps. I will fill the cuts with blocks after nailing in the straps. The ledge that the sill makes is to support the wall planks and insulation.
Quote from: Jim_Rogers on March 13, 2013, 11:13:33 AM
Firetower is one of the engineers I use, as well.
Jim Rogers
Jim,
I'm curious. Do they do all your work remotely or do they come on site (on occasion) ? One question I am tracking down is if the county requires a structural engineer or if a civil can do the work.
Thanks,
John
Quote from: ljohnsaw on March 22, 2013, 01:59:56 AM
Quote from: Jim_Rogers on March 13, 2013, 11:13:33 AM
Firetower is one of the engineers I use, as well.
Jim Rogers
Jim,
I'm curious. Do they do all your work remotely or do they come on site (on occasion) ? One question I am tracking down is if the county requires a structural engineer or if a civil can do the work.
Thanks,
John
John:
I have only had them do my work remotely.
However I do see them often at conferences and other events.
You can pay them to show up if you need them to do that. They will travel, but it can get expensive to have them there.
What's great about these guys is that they have experience in timber framing.
Some engineers do not. And to educate them you're paying for their education.
Good luck with your project.
Jim Rogers
Thank you all on a separate thread on TF Rubies problems. I got it solved - problem was due in part to my creative thinking. I have all my separate layers and I constructed parts of my joints on layers that were later hidden so I could generate the shop drawings - and the hidden parts act funny.
So, on to the next step/problem. I'm green so I need advice from the experts again on my joints. Pictured below is two typical situations I have in my frame. Two apposing braces in timbers. I called them a butt version (in an 8x10) and a bypass (8x10). Will these work? Enough relish for the pegs? (I didn't show those yet).
The Butt version:
(https://forestryforum.com/gallery/albums/userpics/30640/Brace_butt_1.jpg)
(https://forestryforum.com/gallery/albums/userpics/30640/Brace_butt_2.jpg)
(https://forestryforum.com/gallery/albums/userpics/30640/Brace_butt_3.jpg)
And the Bypass version:
(https://forestryforum.com/gallery/albums/userpics/30640/Brace_bypass_1.jpg)
(https://forestryforum.com/gallery/albums/userpics/30640/Brace_bypass_2.jpg)
(https://forestryforum.com/gallery/albums/userpics/30640/Brace_bypass_3.jpg)
I need to re-read Jim's posts on "timber frame rule" on placement of the pegs - but I think I have enough room/relish for them.
Thanks
Hi John,
I knew Ben would give you that solution. I not a 100% sure, but back in this thread I had mentioned "seismic strapping," that we have used, it is a great solution and can even be run in long strips all around the building, it works great! Glad everything is coming together.
I vote "butt"...(There's a T-shirt!!!)
This way the diagonals will all be in the same plane, especially on an outside wall where you don't want some of the diagonals to stick out (into the room).
It might make it look like you had too many "negative beverages" at lunch time prior to assembly of the bents.smiley_beertoast
Rooster
Normally each brace is housed 1/2" under the actual size of the timber or to a standard "inner sized" timber. I haven't opened you last uploaded frame design to check your housings.
I'm not sure if they were there, anyhow.
Are your braces housed 1/2"?
What is your tenon length?
Normally brace tenon lengths are around 3" from the shoulder. If the post is a 8x8 and they are housed 1/2" that leaves 7" of post, with two 3" tenons you should have a 1" gap in between.
Of course if your posts are 7" wide then they may/do butt. And it would be a through mortise.
And you would naturally trim each brace tenon at least 1/8" so that the don't actually touch in the middle.
Brace tenon peg hole layout is normally 1 1/2" off the shoulder and 2" off the bearing end. And the peg hole in the tenon is draw bored in two directions. To pull and hold the joint tight.
Trying to cut by pass mortises will be a challenge for sure. Keep it simple and keep them in line. I vote butt or through mortise to make it easier.
Jim Rogers
Thankls, Jim. So let me restate to see if I got it. The housing on the end of the brace is typically 1/2" smaller all the way around. My braces are 4x6 so my housing would be like 3x5. Now on the timber, the housing typically goes in 1/2". The tenon then "only" needs to go 3" beyond the housing. Did I get that right?
So, are my 4x6's too small and - should upsize to a 5x7?
My post are minimum 8x10 with some braces on the 10" direction so ther will be plenty of space. So on the major beams, I'm not comfortable with a 1/2" housing and I made them 1" deep. Should they be 1-1/2" or 2"? I'm worried about it shrinking and pulling out. I know I need to have enough surface area (including the tenon) to support the load. The load carring capacity of the posts is amazing. The beam calcs give me that area and it suprises me how little is required.
In joining a 8" wide beam to a 8x8 post, should - reduce the housing like the braces? If I don't, it just looks like the beam is sitting in a notch on the post. Poor form?
John,
For the sake of this conversation about braces, I'm going to go over some points, (some probably redundant, sorry) that you make or may not see at this point. One, I have stated this before, is you don't need the braces at all, or at least in an oblique orientation. The oldest timber frames in the world still standing, (and subjected to millenia of earth quakes, and even a nuclear blast during world war two,) do not have any oblique bracing at all...anywhere.
Second, braces as you see them in vintage and contemporary vestiges of the vintage framing, only work in compression, no other way. There is absolutely no reason to make them any bigger than what they are, or house them deeper. Considering that most braces are 3x3, 4x4, 3x4, or 3x5, the larges ever being 4x6, (unless part of a truss system-that is a different thing) your are already way oversized to begin with, as they work in compression, (like a post,) they do not need to be that big, so your size is just fine.
Third point is the tenon is only there to really keep them from falling out of their mortise during raising. Because of there oblique nature and the way wood behaves in shear, you can't get the tenons long enough to do what many believe they are doing...giving more room for a peg. Again, traditionally and in "form following function" they work in compression and do not need to be peg, as the peg is really not doing anything for the strength of the joint and could actually be weakening it. The better forms of this joint are compression wedged, not pegged.
Jim description is 95% accurate in it's outline of the joint, other than the pegging and being draw born, this was never done. The few turn of the century frames that started this practice, (we still only have theories why) present as failed 80% of the time, under examination while dismantling them. When the peg does do something, it appears to be during raising, holding the brace in place while the frame is raised, and in those frames, are smaller, 3/4" to in size. We have even noted that in some of these frames, the connecting girt (beam) has the pegged section of the brace at the top, while the lower is held by a compression wedged on the bottom portion of the brace (sometimes under the tenon, sometime over)
This has been a long running debate within the academic circles of timber wrights, to peg or not to peg. When ever test are conducted, the pegged braces fail in relish of the tenon. I would also point out, than many (most?) traditional tenons are only 2" to 3" long on average, maybe 3.5". It was only in the later half to the 19 century that pegging came into vogue, my theory being we lost so much oral tradition during the civil war, that habits started to form that were based on assumption not good practice or instruction. Below is a short quote from a master timber wright, PE and historical Restorationist, Rudy Christian:
QuoteI find that barns built in the last half of the 19th century in Ohio are as likely to have pegged as unpegged braces. My own engineering background temps me to believe that the carpenters were well aware that braces are meant to work only when they are being pushed on, or "in compression". That being the case, pegs were not needed, and in fact could work against the frame in certain conditions.
First, if you're going to have all that framing for windows and doors, why don't you eliminate the braces on those walls and instead just use a straining beam at the top of the window or door? I call them straining beams, not sure if that's their technical name. It's where you drop a beam some distance from another, like you see in some Chinese timber frames. Second, my frame sure wasn't stiff before we installed the osb on the outside. I can't imagine that metal straps will add the requisite rigidity. Maybe I'm I missing something.
Quote from: ljohnsaw on March 29, 2013, 11:17:12 PM
The housing on the end of the brace is typically 1/2" smaller all the way around.
No, not all the way around, only the post or beam has a housing on one side.
That is if you're using square rule edge layout. With square rule edge layout the housing is on the post or beam. The tenon is "bare faced" on one side.
Like this:
(https://forestryforum.com/gallery/albums/userpics/10095/Brace_tenon_end_view_with_labels.jpg)
The housing looks like this:
(https://forestryforum.com/gallery/albums/userpics/10095/E9_picture_of_shoulder_to_shoulder.JPG)
QuoteNow on the timber, the housing typically goes in 1/2".
The housing is measured from the layout side/reference edge at the arris of the timber so if the timber is truly an 8x8 then the housing is 1/2". But if the timber is oversized it is still draw to 1/2" under. If that is your "general frame rule".
When you design a frame you establish some "general frame rules" and these rules guide you to make all the joints correctly. And with every rule there are exceptions.
One exception is that the brace is not reduced in size.
If the timber is undersized the the housing will be less. It could be only 1/4". You have to understand where you "pull" your measurement from. You can't just take a rough sawn timber and cut a 1/2" housing in from the surface. It has to be laid out correctly from the arris regardless of the actual sizes of the timber.
QuoteThe tenon then "only" needs to go 3" beyond the housing. Did I get that right?
Yes that is right.
Again there are exception to the rules. Another one would be if this was a "tension" brace. But as it has been mentioned most braces work in compression.
If you want a "traditional" looking frame then you would/could use the braces.
In 2002 I was involved with a guild project where we dismantled a barn build 15 miles north of Boston in 1856. Every brace in this barn was pegged. And there were lots of braces.
When we restored this barn, another part of this guild project, and raised it, we put in all the braces and pegs again.
Quoteare my 4x6's too small and - should upsize to a 5x7?
I have not opened/downloaded your frame design. Without looking I can't say for sure but most likely no. They should not be upsized unless your engineer says so.
QuoteShould they be 1-1/2" or 2"?
No, it is my opinion that they should not be made larger. Unless your engineer says so. Again, you could be spinning your wheels until your engineer gives you some details.
I do understand that you want to use "your" engineer. But if he doesn't have any experience in timber frame design engineering then you're paying for his education.
This is why we use engineers who are experienced in timber frame design and loads on these frames.
QuoteIn joining a 8" wide beam to a 8x8 post, should - reduce the housing like the braces? If I don't, it just looks like the beam is sitting in a notch on the post. Poor form?
I have not reviewed your frame design. Every design is different. Shrinkage is a concern for sure. You engineer will/should advise you if your housing are deep enough to create a shelf for the beam to sit on and hold the load. If he can't do that then hire another engineer who has experience with timber frame design and loads on them. You know who, you've already spoken to him.
Good luck and keep asking questions.
Jim Rogers
Quote from: ljohnsaw on March 29, 2013, 11:17:12 PM
In joining a 8" wide beam to a 8x8 post, should - reduce the housing like the braces? If I don't, it just looks like the beam is sitting in a notch on the post. Poor form?
For square rule, your timbers will be a over-sized for your joints. To join the beam to the post you will have to taper the beam down to the housing dimension.
(https://forestryforum.com/gallery/albums/userpics/17998/peg.jpg)
For knee braces to avoid the need to taper, I cut them over-sized on the saw mill. Before cutting the braces, I plane the stock to exact dimension.
Hi John,
First let me tell you that your questions are great, thanks for taking the time to ask them. I gave you some feed back already about the braces, and want to stress to you, (if I sounded other wise,) that
Jim's guidance is awesome. Where he and I differ is only academic timber wright "stuff," Follow his guidance about the braces, if you are going to use them. (minus the pegs of course... :D :D :D)
Hello Witterbound,
QuoteWhy don't you eliminate the braces on those walls and instead just use a straining beam at the top of the window or door? I call them straining beams, not sure if that's their technical name.
These are call "nuki beams" in Japan, and they have counter parts in most Middle Eastern and Asian framing. Your use of "straining beam" is a little miss placed, but I understand why you would call it that, and it isn't really wrong. A straining beam is part of a truss assembly, usually in covered bridges, but also the beam that spans the top of Queen Posts are called straining beams. Most of the frames I facilitate do not have oblique bracing, they are exactly as you describe, and yes very similar to China, or most of Asia.
QuoteI can't imagine that metal straps will add the requisite rigidity. Maybe I'm I missing something.
The straps are great for stiffing a frame, and they make the PE's so happy. As a traditional timber wright, I do everything in my power to do the frame as they had been done, but will add these straps afterwards because they do work so well, and it makes the PE math work much better. In our frames with the horizontal bracing modality, we get the required stiffness the PE is looking for and the flexibility that the frame needs to endure time.
Hey Jim,
Didn't want you to think I didn't agree with your brace advice...it is really good. (minus the pegging of course. :D ;)) I agree, many, if not most frames after 1850 have pegged braces, especially in New England, but for the majority and prior to this time, it isn't true. We had just been discussing this in Michigan frames and those before 1850, in most regions. All the evidence, and engineering points to the peg as being useless if not actually weakening the joint, wedging is much better.
Regards,
jay
Jay/Jim,
Please take this the right way - I find your differences - and disagreements - amusing AND informative. You both have your traditional ways that you would like to see kept alive - at least that's how I interpret your individual opinions. What I'm striving for is to build a cabin to what my mind's eye sees and that would be the more North American style with big beams/posts and braces. My goal is also to be "green" - maximizing the use of local materials (preferably from my land) and minimizing the use of processed wood like plywood or OSB unless engineering necessitates it.
Jay,
I think I may have stated it before - while I do like the look of some of you projects, I don't have the time or resources (money mainly) to fight the engineering academia out here in earthquake-central! :D ::) I want to build this cabin in MY lifetime, not may grand kids!
That being said, I see the merits of pegs to hold the frame together while lifting. The joint itself provides the strength (in compression). To me, personally, I don't see the peg providing much strength in tension as there is little relish to resist and the joint is not meant to be in tension. When you mention wedges to hold the braces in place, I'm assuming you are sliding them in the top side of the joint, in-line with the brace - correct? Use something like a 2x4 and a mallet to drive it in? Given the shear number of braces in my plans, I'm all for using wedges vs. cutting so many pegs an drilling so many holes!!!! :o I'd like to see a picture or even a drawing of this practice.
Now, as far as the square rule, etc. I've got sort of a problem with my drawings. Engineering the load, I need to use a 10x16 - so that is what I draw. I know my beam won't be that exactly, I'll be sure to oversize it a bit when cutting. In fact, everything that I cut I will add a percentage for shrinkage such that I will be over the stated size. Should I draw my beams to be say 10.5 x 16.5 so the housing comes out right? I chose not to do it that way. Am I wrong? My shop drawing will have all the dimensions for the cuts so do I bother with that fine point? As long as I indicate the working face and adjacent face, all should be good, right? It would be a relatively easy modification, but does it really matter? :-\
I'll see If Don has any photos, maybe Rooster does. Did the Engineer say you needed these big timbers, or is that just the look you are going for? Most often, if there shimmed/wedged, it is from the bottom (outboard,) as Rudy suggested, however with housed braces this may not be best aesthetically. The other is wedging from the top, (inboard.) Which do you think you would like to see?
Regards,
jay
Quote from: Jay C. White Cloud on March 30, 2013, 10:35:33 PM
I'll see If Don has any photos, maybe Rooster does.
Thanks
Quote from: Jay C. White Cloud on March 30, 2013, 10:35:33 PMDid the Engineer say you needed these big timbers, or is that just the look you are going for?
I am still working on getting a quote for engineering services. I did the load calcs myself from the original 45° roof slope. The roof snow load dropped from 116 PSF to 78 PSF when I bumped up to the 53° slope (16/12). I was able to downsize the rafter from the 6x9's to 5x8's (actually 4x8's would work but I'm going stouter) at 24" OC. I need to work down the frame. I suspect the "purlins" will be able to downsize as well. Right now, they are 8x12 on the lower and 8x15's on the mid and ridge. The tie beams carrying the queen posts have the most load and they are 10x16's.
Quote from: Jay C. White Cloud on March 30, 2013, 10:35:33 PMMost often, if there shimmed/wedged, it is from the bottom (outboard,) as Rudy suggested, however with housed braces this may not be best aesthetically. The other is wedging from the top, (inboard.) Which do you think you would like to see?
Regards,
jay
I was thinking the wedging going in at the top since the bottom is more of the bearing surface and it would be a neater look/cleaner installation. Now, I was thinking this is a really thin (like 1/4" down to nothing) wedge but it probably isn't, is it? Is is more like 1/2" to 1" thick with a little 1 or 2° taper?
Hi John,
Now I understand the sizing, it makes since, and doesn't sound bad at all. The more I study the frame, the more of you I see in it, and that is a good thing. To often when you facilitate a frame with someone, you can influence too many elements, and it begins to look...well imbalanced. If you listen, and follow certain design standards, and elements you soon begin to work in concert with that person. I love the roof pitch, it is the one I use on many of my frames, 53° or 37°, it is a classic pitch, and part of the "golden mean."
Did you get a hold of "Fire Tower Engineers?"
I think from the top will look nice on the braces and could even be a signature statement if you use a wood like Madrone. I'm going to take one of your joints in the frame and play with it and send it to you. You let me know what you think.
Regards,
jay
Yes, I'm in contact with Fire Tower.
Jay, the joints in the posted plans are not correct. They are just drawn and not done as TF Joints. Also, I have changed them quite a bit since my last skp file posting. Let me know if you want me to send you the plan as it stands now - more work to do - but the basic timbers and braces are done correctly (I think) now.
Quote from: ljohnsaw on March 30, 2013, 07:38:44 PM
Now, as far as the square rule, etc. I've got sort of a problem with my drawings. Engineering the load, I need to use a 10x16 - so that is what I draw. I know my beam won't be that exactly, I'll be sure to oversize it a bit when cutting. In fact, everything that I cut I will add a percentage for shrinkage such that I will be over the stated size. Should I draw my beams to be say 10.5 x 16.5 so the housing comes out right? I chose not to do it that way. Am I wrong? My shop drawing will have all the dimensions for the cuts so do I bother with that fine point? As long as I indicate the working face and adjacent face, all should be good, right? It would be a relatively easy modification, but does it really matter? :-\
In my opinion, you draw the plans to dimension you will use. Your timbers will be slightly over-sized. For example if you are using 8 x 10 beams you might cut them at 8 1/4 by 10 1/4. When it is time to do the layout, a mortise in the post would be housed exactly for an 8 X 10 beam. When you are working on the beam at the housing portion you par back the non reference faces as needed to make it exactly 8 x 10. You can see that in the photo I posted above. The beam is cut back on the bottom so it fits properly in the mortise. You don't need to include this detail on you plan...you just need to add it and cut when you do the layout.
I have incorporated engineering changes as suggested by Ben of Fire Tower. I have a contract with him to move my project along. I've cleaned up my drawing to a level I was comfortable submitting to him. Now I feel like I'm back in High School - I submitted my term paper and I'm hoping to get a passing grade ;)
I'm meeting a well driller (that I used 22 years ago) at my property on Friday. If we can find water, I'll be very anxious to get my plans finalized and off to the building department. We have had a very mild winter (only about 4 or 5 feet of snow this year compared to 19 feet two years ago) and unseasonably warm weather. It has been in the 50s and 60s at my property while being in the 70s and 80s here (near Sacramento). There is still a chance of a late storm to muck thinks up but that is waning every day. The next 10 days are predicted to be mostly clear with afternoon thunder showers - almost a summer pattern.
If I can get water in the next week or two, I'll be ordering my Faswall blocks since there is a 6-8 week lead time. I might actually get further along than I thought this year!
I'm pondering what single piece of equipment to buy to aid in the building of my cabin. I'm not going into the lumber business so I'm NOT considering a FEL.
Here's my thoughts:
My foundation will be 10' high with 7 or 8' above the soil. On top of that, the timber frame side walls will extend ~14' with the peak at nearly 30' above the sill. I will be needing to place the common rafters, roof planks, possible plywood, rigid insulation and metal roofing way up there.
A knuckle boom (truck or trailer type) would get me up there but has limited load capacity (~500lbs?).
An extended reach fork lift (the kind with the four big wheels, all wheel drive/steering) would be able to lift much more and probably reach farther.
I would use a safety harness slung over the peak to anchor myself. Comments on either or any other suggestions? What is the going cost on either of the above (in your area)? I would plan to sell whatever after I'm done. I think it would be much more cost effective than renting!!!
With your distances it looks to me like you will need some type of crane assembly (lifting 20-30 feet for your plates and ridges). I know of builders that purchased an old truck with crane assembly and then resold it after their project.
In the next year I am building a smaller timber frame in a remote area. I will be installing a derrick type crane built from logs and hardware we welded up. This will be installed at the beginning of the project and positioned to move timbers for cutting and installed such that I can also install the timbers on the building.
To make your higher lifts you could just set up a lifting shear or Gin pole. Rigging would run you about 1K.
Years ago, I purchased an Oliver 880 for 3K. Probably the best investment I have made. I've used if for hauling, pulling, lifting, anchoring, attaching a gin pole to the bucket to get more reach, etc. Often, after felling trees, if they were too large to pull with the ATV and log arch, I would have been stuck without the Oliver. I also have enough scaffolding that I could set up an access the ridge.
The machine you purchase should be based on your needs. Are you felling trees? Running a sawmill? Where do you have to move your timbers? Are there roads? Paths? Etc.
For my project a tractor, an ATV, an Log Arch was the right combination. I really like the bobcats for general use; however, I didnt' want to spend that kind of money. Even used they are quite spendy.
(https://forestryforum.com/gallery/albums/userpics/17998/DSC01785.JPG)
(https://forestryforum.com/gallery/albums/userpics/17998/loader.jpg)
(https://forestryforum.com/gallery/albums/userpics/17998/1998/DSC02468.JPG)
I used a variable reach fork lift. It was a big one (6,000LB). Cost me $414 per day or $1011/wk. I rented it for the whole week. It was $165 to deliver it, but my place is 60 miles from where I rented it. It was well worth the money.
(https://forestryforum.com/gallery/albums/userpics/11185/DSCN0282.JPG)
(https://forestryforum.com/gallery/albums/userpics/11185/088.JPG)
You need something to move and store the timbers when cutting the frame, then something entirely different to raise your frame. Like a forklift or bobcat now, and a crane or telelifts later.
For raising you may get a better rate for renting one if you rent it for a month.
I'd at least check into it and see.
Jim Rogers
when it comes to building I think there are few pieces of machinery more handy then the 4 wheel drive tele lifter. if your working with others you can build some kind of bucket (thats what we called) which could just be a big pallet with some fences around the side, one guy sits inside the bucket while the other controls the vehicle and can bring it to each window or whatever else.... that is what I would look into....