Getting enough information to get underway as far as planning

[jimdad07]

I have been lurking and reading on here for days now, I have so far gone back about 12 pages of old threads and have been doing a lot of reading and rough drafts of the different joints.  I am starting to get a plan forming in my head.  Here is what I have come to so far:

1. Material: I have decided to be patient and get timbers that I can box the heart wood for the most part.  I will use the free of heart wood method only with the most strait grain poplar that I have on hand.  I also just got access to a lot of red pine for free as well as some younger poplar that is arrow strait but will allow me to get some good 8x8's out of them.  There will be some red oak thrown in here and there, should end up with a Hienz 57 blend of wood.

2. Joinery Method: Will be using the square rule method for this as I have a small space for doing my notching and fitting etc.

3. Basic design: Looking at a wood shop/saw shop with hopefully an open floor plan.  Input on my design will have some bearing on this.  The basic structure will be an 18'x24' with the eave walls being 12' high to accommodate an attic.  The design will be a tie-below plate application because it will be much easier for me to figure the joinery and will make it easier to put a floor in for the second floor.  I plan on 4 bents with 8' in between them, this may be over doing it some but I live in a wind tunnel off of lake Ontario and the St. Lawrence river, couple that with the snow load of living in an area that gets our fair share of lake effect and there will be some decent stress on the structure.  The way my property lines up the prevailing wind will be hitting the long side of the shop.

4. Timber Sizing: Here is the part that I have not figured out so much.  I was thinking of 8x8 posts with 8x8 plates, as far as the tie beams that will also hold the floor joists, I was figuring on 6x10's as there will be a pretty good load from the second floor from using it for storage.  I would like to have the bents continue to the peak using through mortises to tie the rafters from each side together and then run 4x6 purlins horizontally on 2' centers in between  8x8 rafters to screw the sheet metal roof to it.

5. Finishing the outside walls:  Plan to do board and batten, hope to let the boards air dry as much as possible before putting them on, will most likely be a mix of box elder and poplar as it is about the easiest wood to come by around here because people see it as useless for anything, may be some big willow thrown in as well.  All depends on what I can scrounge up.

Feel free to give all the input good or bad you want to to point me in the right direction.  I downloaded the sketchup program plus I have turbocad on my computer so as soon as I finalize my plans and draw them up properly I will post them for review.  Thanks in advance guys and gals.

[piller]

Sounds like a good project.

OK, 18 feet wide, 24 feet long, ties below plate, 4 bents spaced 8 feet apart.  With 8x8 posts and plates, and an 18 foot span, and wanting to have a second story I might think about up sizing the 6x10's to 8x10's for the tie beams.  Also, how would you support the second story, would you be notching out material from your tie beams, if so that would weaken them.

I'm not real clear on your roof structure, it sounds perhaps like a principal rafter common purlin roof, but those are typically found on tie above plate designs.  How many 8x8 rafters, what is the rafter spacing, the 8x8 rafters will be joined at the peak with a mortise and tenon joint, will the rafters sit on the plates and with what joinery, a step lap?  What is the roof pitch?

What about the foundation, post support, will you have sill timbers? 

[jimdad07]

Sounds like a good project.

OK, 18 feet wide, 24 feet long, ties below plate, 4 bents spaced 8 feet apart.  With 8x8 posts and plates, and an 18 foot span, and wanting to have a second story I might think about up sizing the 6x10's to 8x10's for the tie beams.  Also, how would you support the second story, would you be notching out material from your tie beams, if so that would weaken them.

I'm not real clear on your roof structure, it sounds perhaps like a principal rafter common purlin roof, but those are typically found on tie above plate designs.  How many 8x8 rafters, what is the rafter spacing, the 8x8 rafters will be joined at the peak with a mortise and tenon joint, will the rafters sit on the plates and with what joinery, a step lap?  What is the roof pitch?

What about the foundation, post support, will you have sill timbers?

As for supporting the second floor, I wanted to tie into the main posts.  I think the proper term for what I want to do is an H-bent?  I see what you are saying about 8x10's.

I was thinking of a 5/12 roof pitch with the 8x8's lining up with the main vertical supports and purlins running horizontally every 2' on center.  As far as where the rafters meet the plates, I wanted to do the hidden bird's mouth design.  Do you think a standard rafter setup would be better?

I have some telephone poles that were left after some replacements the utility company did.  These are the old creosote poles and they are in great shape.  I wanted to use those for piers buried below frost line and backfilled with gravel.  I have used sonotubes many times and am not the biggest fan, I think the poles last better than the piers with the frost action up here.  There will also be sill timbers, need advice on sizing them, I would think that 8x10's for this purpose would be ok.

[Jim_Rogers]

What is the snow load for your area?

[jimdad07]

What is the snow load for your area?

The snow load in my area is 60. 

[Jim_Rogers]

What size purlins were you thinking of using?

What type of wood?

Jim Rogers

[jimdad07]

What size purlins were you thinking of using?

What type of wood?

Jim Rogers

I was thinking of 4x6's cut out of red pine.  I was going to use poplar (that's what we call cottonwood up here) but I thought that maybe it wouldn't be strong enough for the longer span between the principal rafters (hope I put the right name to the rafters).

[Thehardway]

Jimdad,

Cottonwood has little value if any for framing purposes regardless of size and grain. Use it for your board and batten siding.  Use the red oak for posts and the Red Pine for rafters and purlins. Perhaps you could find some EWP or Hemlock to use for the beefier tie beams?  I agree you might want to upsize a little from the 6X 10...  Use the load calcs. at the top of the forum.  I would have a little concern about rafter spread using principal rafters in an 18' span  5/12 with a 60lb snowload and the high kneewall arrangment.  I think I might increase the pitch or go to a kingpost or queenpost truss design.  This would also help support the tie beams for your floor support.

None of the species you mentioned so far are much good for sills.  They are all quite low in rot resistance and insect resisitance.  You might want to see if you can source some white oak, or black locust for the sills.  What kind of spacing are you planing on for the pilings? What will the main floor consist of and how much load does it need to support? how will it be protected?

[piller]

I was just looking at http://www.timberframecottage.com/su/ and saw a timberframe model (Example.skp) that may or may not be similar to what you are thinking about.  You can take a look at that web page, or I uploaded an image to my gallery here but I don't know yet how to add it here. 

In this model the rafters connect to the post tops, not to the plates, is that what you are planning?  Also in this model:
   * the plates are not continuous
   * there is a post supporting the center of the tie beam
   * the roof pitch is steeper than 5/12
   * the rafters get extra support from queen post structures

[Raphael]

I'm thinking 8x10 or deeper for the tye beam, 8" gives you more room for (and between) joist pockets and you know one day you'll have a great stack of green lumber drying up there.  ;)

[jimdad07]

I'm thinking 8x10 or deeper for the tie beam, 8" gives you more room for (and between) joist pockets and you know one day you'll have a great stack of green lumber drying up there.  ;)

You have read my mind.  There will be some green wood drying up there for sure.  I appreciate the input quite a bit, I am not not clueless to building by any means, most of us who are in the trades up here where I am have done a lot of building at some point but this is new ground for me.  As far as using the cottonwood (what we call poplar up here) I am trying to limit it as much as possible for framing material but I cannot afford to buy logs for this so I have to use what I can get and hope it works how I need it too.  I just found two nice big strait white pines out back that are just about blown over so they will come down and get used for the project as well.

[jimdad07]

The planning process is still going.  I have some good news for my project and that is that I got a line on a stand of white oak and hickory trees that are supposed to be 12" to 18" trunks and and clear for close to 20'.  Supposed to be close to 60 trees that this guy wants out of there and he will split the logs with me if I can cut him some lumber on my saw mill.  Not a bad deal, I can cut my timbers on his property as I go and bring them home cut.  Hopefully it's as good as it sounds.  I know the guy and he's usually pretty strait forward.

[Piston]

Welcome to the forum. 

Your ideas sound a lot like the shed/workshop I would like to build.  It is 16'x24' but only 3 bents.  I am using 8x12's for the tie beams on the end bents, and a 10x12 for the center tie beam.  I went with the 10x12 not because of strength, but because I will be notching out a decent amount of wood for my loft floor joists, so the remaining wood with no joinery cut into it will be around 6 or 7 inches left or so. 

In fact, now that I write this out, it makes me think maybe I should go even wider, but I think that should be sufficient. 
I am having my plans looked over by a smart and experienced fellow who I have to say good things about because he'll probably read this  :D