I thought I would try and get some opinions on a truss design for the garage I am building this spring. I priced out a standard 36' span truss at the local lumber yard and they were running around 90 bucks each. I figured out my materials and I should be able to save at least half by doing it myself.
Anyways, the garage is going to be 36'x36'. I plan on running a beam or header down the middle to take some of the load so the truss' are actually only having to span half the distance or 18'. I was going to use 2x6 for the bottom cords and 2x4's for the rest. I also plan on using plywood for the gussets and nailing and gluing all the seams and joints. The truss will be of an an attic type design so I can implement some cold storage area. I'm hoping someone can chime in for a little advice. I can send out a pdf of the design if you want to take a look at it. Let me know what you guys think....
jev

 

If your going to run the beam in the center then just stick build your attic, the center bearing in an attic truss does more to limit deflection than to actually absorb load since there are no webs in the "room area" to locate over the beam. I had designed a plan for a 30X30 that used a Glu-Lam beam down the center of the garage. It beared on the back wall and on the wall section between the garage doors. The contractor framed his side walls at 12' and ran a 2X10 band around the inside of the wall that he used to attach his 2X10 Joists to via hangers. The other end of the joists sat on the Glu-Lam Beam. If you set your garage ceiling hight to 8' (to the bottom of the 2X10 band) then the 12' side walls form a 3'-2" AFF Knee Wall to stick frame your roof rafters off of. I think he used 2X8 Rafters on 24" Centers with a 2X6 Collar Tie on every other rafter. The 3'-2" knee wall really helps you maximize the space up there and your room is as big as the shop below. In a truss about the best you could do there would be a 16' wide room, and that may be pushing it a bit... I would have to run it and see but you will still lose 10' of space on each side for the webbing. The advantage is that the trusses will clear span the garage. If you don't have a problem with a beam in there and possibly a post in the middle you can stick build it and save yourself a bit of $$$.

I've designed some field frame trusses for a couple of guys on here before, but my access to that info is limited because I work for a steel truss company now, and my wood truss software is still packed away in a box somewhere in GA. I wouldn't recomend field framing the attic trusses with that long a span though, there is alot of force at the joints and your plywood gussetts would have to be huge to absorb it properly. You might as well plywood the entire truss less the room section. If you decide to go with trusses I would recomended just buying the metal plated trusses there locally.

 

Or you could use 12" I-beam for a truss and one is all you would need. The end trusses could be c-purling.

Are you stuck on lumber?

 

Many local building inspectors will require a PE stamp on your plans and also a certification stamp on any truss.

 

why not just build a stick roof? it is easier than making headers, not sure what the difference in cost would be though.

 

If you're using wood, see if there isn't a truss mfg. somewhere near you, try dealing with them directly, although the prices doesn't seem bad. But you will use more muscle to get them in place vs stick building.

The materials you mentioned do not sound stout enough.

The replies you've already got seem good.

Check on the internet for garage plans, don't have to buy them, just look. And/or go to a large book store nearby, there are books just for this type project, again, you don't HAVE to buy, just browse the pages, you should be able to get more ideas.