Can I use rigid styrofoam on top of top plate to minimize thermal bridge from trusses
Hello,
I was wondering if its suitable to install a truss on top of a sandwich styrofoam between 3/4 ply and the top plate of an exterior wall, Sort of like putting a SIP on flat. Can the SIP support the point load of trusses for lets say a roof needing to support 100 psf?
Thanks
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
You can, but you would have to have an engineer run the numbers and specify the the fasteners, along with the minimum density of the foam. I'm not sure what horrific thermal bridge probably you'd be solving with that approach. In hurricane zones the thermal bridge of the required framing ties would defeat any gains at the margin of thermally breaking the timbers.