At 09:24 PM 2/11/2012, you wrote: >What is lighter, the sheathing plywood used on the fuse, or thin foam >covered in BID? I've seen some guys fill the gaps between structural >members and cover with glass. Anyone have experience with this technique? >What's the weight diff? > >Phill ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
I don't think the real question here should be the weight but the strength / characteristics of the two materials. The compression / tension characteristics of the two materials will differ considerably and you can't just substitute one for the other based on weight. I'm no engineer but I'd bet a lot of money that the compression strength of a thin layer of glass, even with a foam core, is a lot less than plywood. You could either over build, with a great weight penalty, or have a structural engineer design a structural to handle the loads using the new material. Why not just build to proven plans? Larry Flesnr