28'x50' Barn, broke ground this weekend

[jimdad07]

I have few questions on sizing bracing as well as collar ties.  I want as much bracing as possible in my frame.  I have a pretty heavy wind load where I live off of the end of Lake Ontario.  Are there any rules of thumb for sizing braces?  I would also like to have my second floor wood shop open but if I do so it will eliminate purlin plates and queen posts supporting the roof.  I have sized my rafters to handle a total load of 64 psf, which will have my non gable rafters supporting a total load of 13,446#'s based on my tributary area on each of those rafters.  That gives me a 8x10 EWP with just under a 1/2" deflection based on the loads.  A 7x9 rafter also passed but it has a deflection of .7+".  I guess my question would be how well would collar ties fight thrust at the top plates vs. purlin plates.  I am using an 8/12 pitch for gable end bays and a 5/12 pitch for dormers that will be over the two middle bays.  Hope I explained it clearly enough.

[Jim_Rogers]

First of all a collar beam will only reduce the rafter thrust if it is within 12" above the rafter foot at the plate.
In any other elevation the collar beam is in compression, that is preventing the rafters from sagging.

You can make the braces any size you want.
Normally larger braces are 4x6 but you can make them 4x7 or 4x8 if you wish. Even 6x6 if you want to, you just need to lay them out right and cut them so that the fit tight. Always in pairs, so that they are opposing.

The rest of your question are best answered by an experienced timber framing structural engineer.

Jim Rogers

[jimdad07]

Thanks Jim, that's what I wanted to know.

[jimdad07]

Pouring concrete this weekend and my logs are close to being delivered.  Can't wait for the concrete to be finished. Then I can get excited.

[jimdad07]

Still waiting on logs.  The logger I'm dealing with is into a patch of white pine that he's setting aside logs that are going to fit the bill.  He's bringing me 20' logs that I will be able to cut my 10"x16" tie beams out of.  Should be enough on the load for my bents and girts.  I have three 30" diameter pines out back in the woods that are blown half way down with good 30' of clear stem to the first branches.  Hopefully I can get some rafters out of those.  Going crazy waiting and reading old threads, ready to start doing!  Making redundant posts just isn't cutting it.

[jimdad07]

I know you guys are probably about tired of reading the redundant posting so I wanted to ask some joinery questions starting with my first floor framing.  I am in the phase of designing my joinery and I have a good idea of what I want to do after several hours of reading old posts, etc.

1:  I'll start with my tie beams as they will be the most complicated for me.
-my tie beams are 10"x16" EWP.  I have read several posts about cutting my tenons at 1/4 the width of the beam.  This would put me at a tenon 2.5"x16".  Keep in mind that I plan to cut a shoulder in the bottom of the joint at 3/4" going to 0" by the time I get to the top of the joint in the 10"x10" post.  Is it acceptable to use a 2" tenon for this joint?  Also I would like to make this a through tenon so I can maitain plenty of relish with the amount of tension on the joint.  I would also like to double peg this joint with ash pegs that are 1.5" diameter.
- next are the scarf joints for the tie beams.  I am interested in using a stop splayed scarf joint with ash wedges with the joint being supported by a knee brace and not the post.  If I am understanding my building loads right this joint will be in high tension due to rafter thrust at the top plates.  Is there a better option for this joint that a newb like I can understand? Am I also right in assuming that a beam with a depth of 16" will need a scarf joint at 64" in length?
- next question: stub tenons connecting my center posts to my tie beams.  Does the same rule apply to sizing stub tenons as regular tendons?  Also what is a good height for the tenon on a 10"x10" post tying into a 10"x16" tie beam?  Also I want to recess the post into the tie beam a 1/2".

Plenty more questions to follow.

[Dave Shepard]

I would use 2"/2" joinery, unless engineering dictated otherwise. When you try to cut joints without chisels and drill bits the exact size, efficiency goes out the window.

[Brian_Weekley]

Hi Jim,  Do you have a drawing you can post of your building?  Sorry, I'm thinking you may be using incorrect terms for the timbers you're describing.

[beenthere]

Did you ever do the pour on the slab? Saw pics of removing dirt and wondered....

Or is it awaiting the posts first? and thus on the design...

[jimdad07]

Hi Jim,  Do you have a drawing you can post of your building?  Sorry, I'm thinking you may be using incorrect terms for the timbers you're describing.

I have to make them to scale and take a picture of them to post.  When I say tie beam I mean the beam that spans from one wall to the other and supports the second floor.  The posts I'm referring to are the upright posts that will support under the tie beam as well as the posts that will make up the outside walls and carry the top plate.  You'll have to forgive me, I'm just trying to learn everything I can before I finalize the joinery and make sure I'm not missing any steps in the process.  I figured the better game plan I have the better my barn will come out.  I really need to have an engineer examine my drawings but money is a very large issue right now with the farm and breakdowns this summer sucking my barn fund down to just enough for one load of logs and the concrete we poured last weekend.  That's why I'm asking so many questions and running so many numbers.  I will probably be over engineered but that's much better than being the other way.  Your patience and responses are appreciated.

[jimdad07]

Did you ever do the pour on the slab? Saw pics of removing dirt and wondered....

Or is it awaiting the posts first? and thus on the design...

Slab is poured, barely beat the rain and covered the concrete right in time.  I know the footprint I want and the design is pretty firm in my head as well as the sizes of the timbers.  I have a rough print drawn up but I don't want to finalize it until I have the joinery figured out.  I have to sit down and post the pics.

[ljohnsaw]

Jim,

When I designed my cabin (doing the foundation now), I downloaded a free version of SketchUp.  Quite a learning curve but once mastered, you can draw up just about anything really fast.  It has add-ons that will help with the joints later on in the process.  I did the load calcs (with the help of the Tool Box on the left, bottom).  Then I worked with Fire Tower Engineered Timber, Inc - recommended by a few here.  They were VERY flexible.  I maintained control of my plans making changes that they requested/required, saving myself a lot of money on a draftsman or their time to do the changes.  I eventually had to buy a version of SketchUp to get Layout, which turns your 3D model into normal architectural plans that you annotate and can submit to your building department (if a permit is required).

SketchUp then will generate the shop drawings you need for doing all your joint cuts - all you do is add the dimensions by using the tape measure in the program.

[jimdad07]

Jim,

When I designed my cabin (doing the foundation now), I downloaded a free version of SketchUp.  Quite a learning curve but once mastered, you can draw up just about anything really fast.  It has add-ons that will help with the joints later on in the process.  I did the load calcs (with the help of the Tool Box on the left, bottom).  Then I worked with Fire Tower Engineered Timber, Inc - recommended by a few here.  They were VERY flexible.  I maintained control of my plans making changes that they requested/required, saving myself a lot of money on a draftsman or their time to do the changes.  I eventually had to buy a version of SketchUp to get Layout, which turns your 3D model into normal architectural plans that you annotate and can submit to your building department (if a permit is required).

SketchUp then will generate the shop drawings you need for doing all your joint cuts - all you do is add the dimensions by using the tape measure in the program.

The toolbox here is excellent.  I ran all of my post and beam sizes as well as figured the rafters with it.  I made notes of all the calcs so I can post them here when the plan is 100% set.  In a previous life I took four years of architectural drafting and mechanical drafting so I have a decent if not rusty handle on that end of it.  Go figure I ended up in construction and finally into industrial HVAC for the past ten years.

[jimdad07]

Jim,

When I designed my cabin (doing the foundation now), I downloaded a free version of SketchUp.  Quite a learning curve but once mastered, you can draw up just about anything really fast.  It has add-ons that will help with the joints later on in the process.  I did the load calcs (with the help of the Tool Box on the left, bottom).  Then I worked with Fire Tower Engineered Timber, Inc - recommended by a few here.  They were VERY flexible.  I maintained control of my plans making changes that they requested/required, saving myself a lot of money on a draftsman or their time to do the changes.  I eventually had to buy a version of SketchUp to get Layout, which turns your 3D model into normal architectural plans that you annotate and can submit to your building department (if a permit is required).

SketchUp then will generate the shop drawings you need for doing all your joint cuts - all you do is add the dimensions by using the tape measure in the program.

BTW, I've been paying attention to your build, quite a site you have there.  It's going to be a perfect setting for your cabin.  The amount of rock you have there looks like a good time for working around them!

[jimdad07]

Guess I better put some figures down as I work towards the final draft.

Barn size: 28'x50'
Number of bents: 5
Bays: 4
First floor ceiling height to bottom of tie beams: 12'
Total roof load: 64psf
Total 2nd floor: 80psf
Roof pitch: 8/12 at gable end bays
                -5/12 over the middle bays, reasoning is for more usable space for my wood shop.
When I say bays for the roof pitch I'm putting the tributary areas in between the rafters in relation to the bays on the first floor.  I am planning a rafter and purlin roof system, with the rafters lining up with the posts over the outer walls of the barn.

That being said I ran my load numbers through the forum toolbox using the beam and stringer calculator.

Starting with the roof:
Rafters passed all tests with a 8"x10" EWP giving me 0.4" deflection over the span
Purlins that pass are 5"x8" EWP
-planning a T and F joint where the rafters meet at the roof ridge with a single peg
-want to install the purlins in pockets in the rafters and secure with timberlocs (I know that's cheating)
-the tails of the rafters is something I'm undecided on.  I plan on cutting rafter seats into the top plates but am not sure on how I want to work the tails for the eaves of the barn
I ran these numbers for the rafters as if there aren't any purlin plates and queen posts supporting at mid span, my span is 14' measuring from the roof ridge to the outside wall.  A concern of mine is rafter thrust at the top plates if I don't use a purlin plate system.  That concern is battling with the desire for an open second floor.  I will have to go with the safest building practice on this one and most likely use a purlin plate and queen post system.  The other design consideration for a purlin plate and queen post is I will only have one post off center supporting the tie beams and will not be able to carry the load directly to the footers below the first floor posts. 

I'll get into the first floor loads and sizing in the next installment.  Sorry if this is confusing and my terminology probably sucks, but if you guys can decipher what I'm trying to say it would be a help.

[jimdad07]

Good news, turns out there's a FF. Member less than five miles from my house who has cut and built his own frame.  The guy makes wooden boats to boot.  Going to meet up with him next week and pick his brain.

[jimdad07]

Good news for me today, my logs are getting dropped tomorrow night.  I also broke down and will be picking up my band mill next Friday.  Must have been smoking something when I thought I could mill out this frame with my chainsaw.  Figured out my cost just for lumber and I'll still save close to $1000 after buying a brand new band mill.  Very excited about it all.

[jimdad07]

First tie beam is cut.  It is 10"x16"x21' long.  Nine more of these to go and then onto posts.  It's been slow going with all of the winter prep going on but I now have a start.  Let me know if the pics are sideways, been editing and rotating them trying to get them to show up right on the full site.

[beenthere]

Not sideways.. so you are gaining on it.

But put some lines or blanks to separate the pics... helps. Don't get discouraged... we do like pics. 

[jimdad07]

Not sideways.. so you are gaining on it.

But put some lines or blanks to separate the pics... helps. Don't get discouraged... we do like pics.  8)

I'm working on it! I put spaces in the post, I'll try some more.  I'm on a few forums for milling and chainsaws and this one has got to be the worst for posting pics.  I'm spoiled by Tapatalk, start a post, snap a picture and it's automatically put in the post.  Very much enjoying my sawmill, it's sitting on the barn slab.  Glad I bought the extra couple sections of track with the mill, these are long timbers.  I wasn't prepared for the size of the beam.  I rolled it with a peevee after the last cut.  Now I'm not a small and out of shape guy at 6'2" and 212#'s, but I'm pretty sure I lost a nut turning that beam after I was done cutting it!