Will 1″ EPS baffle withstand pressure of dense pack cellulose?
“(If you use rigid foam for your baffles, it probably makes more sense to choose thin EPS or XPS rather than foil-faced polyisocyanurate, to allow a bit of outward drying, however slow, by diffusion. A thin layer of EPS or XPS is somewhat vapor-permeable, while foil facing is a vapor barrier.)”
Will 1″ of EPS be strong enough to withstand the pressure of 12″ of dense pack cellulose ? The plan is to be as airtight as possible in the ceiling, but if moisture does escape, I’m using EPS as a vapor permeable board that also contributes insulation. Would 1.5″ or 2″ EPS still allow vapor to move through but be stronger to withstand the dense pack?
We’ve built a timbrframe that will have cathedral ceilings and an exposed ridge. From the inside out we’re planning air sealed drywall (taped and gasketed), 1×4 strapping, 2×12 rafters 24″ OC, dense packed cellulose, a baffle of eps that is taped and caulked, 2×2 sticks at the top corners of the baffle, 5/8 cdx plywoood, 30 # felt, galvanized metal roof.
I know plywood is an option for the baffle but I would prefer to gain insulate value if I’m creating he baffle in the rafter bay and loosing the cellulose there.
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