I have 30 x 40 block garage with trusses designed for light storage. The trusses have 2×6 Joist or Cord with roof rafters and webs being 2×4. Trusses are spaced 24″ center and the center area is designed for storage. I was wondering if someone would know how to calculate what load these truss could handle. I want to use for light storage but now sure what type of flooring I should use, such as 3/4 -1/2 etc. I will be walking around to store light boxes etc. I tried reaching out to the manufacture of the trusses and the went out of business when the housing market dropped in late 2000. No drywall on joist.
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I've been designing trusses for ~30 years. Most storage trusses we do have a 20 PSF added load in the center area. But that doesn't necessarily mean that's what your trusses are designed for.
Can you post some pictures of the trusses? Lumber species and grades would also be helpful if you can find a grade stamp. And the plate size where the webs meet the bottom chord.
I don't remember ever seeing any decking other than 1/2" which seems to work fine. Just remember it is for light storage only, Xmas decs, empty suitcases, etc. Not big boxes of old clothes or anvils.
I store all my unused anvils in my attic and have never had a problem other than getting them up there.
I have attached a hand drawing with all dimensions along with picture. I built the garage 20 years ago and lost my truss drawings. The manufacture is no longer in business.
I had them design the truss for storage, I have installed some 1/2 osb but it seems to weak to walk on. The trusses are 24" c spaced.
I want to install a thicker type plywood or OSB but want to make sure the trusses can handle the weight. The trusses were designed to have me walk around in the center without giving to much pitch for a steep roof and keeping the garage from being to tall because of 10 ft ceiling height in the garage area. The attic flooring was not specified on thickness.
Few more pic.
Well, there's no doubt the trusses were designed for some storage load. Offhand I'd say the 20 PSF I mentioned earlier is a safe bet. Although it might be 30 PSF. I really don't think it's more than that.
3/4" plywood is only about 3 PSF, so that won't make much difference. And it will definitely have a better feel to it.
Great. Thanks for the info.