CFS Roof Truss Self Weight

[memphiseng]

Does anyone have a good source for the self weight of a typical CFS Roof Truss, and have so far been unlucky. Alpine provides approximate values for wood trusses in the "Encyclopedia of Trusses", but I cannot find similar values for CFS. The only thing I have found is a sentence in the same document that claiming "TruSteel trusses can be as light as one-half the weight of similar wood or "C" channel steel trusses." We've typically conservatively used the same self-weight as wood trusses in our DL previously, but I am now involved in a project where a more accurate, yet still conservative, estimate would be useful.

CFS is obviously lighter, but not sure I feel very comfortable reducing the weight by half based on a single sentence in what amounts to a sales brochure.

 

[jayrod12]

Perhaps you need to figure out how much lighter they would weigh to work for whatever issue you are checking. Then compare that allowable roof dead load to say a typical wood truss roof dead load and see what the reduction in weight would need to be. Maybe you only need to cut 10-15% of the wood truss weight out, which I wouldn't think is unreasonable.

 

[dhengr]

Memphiseng:
Why not ask a couple CFS truss designers and builders, their engineering depts., not their sales reps., for some engineering guidance and help? They might have some info. on the subject. Give them your bldg. type, span lengths, local design loads, etc., and ask for some prelim. designs and weights with the thought of getting the job later.

 

[Lomarandil]

What kinds of spans and loads are we talking about?

I've designed CFS roofs with total self weights between 80-200 Pa (minimum cladding), depending on the purpose.

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just call me Lo.