What combination of foam insulation for this wall?
I’ve got a wall that has seen substantial water damage, and the existing fiberglass insulation is destroyed (along with the studs, sheathing, and sill, but that part I’ve got covered).
The existing wall was:
1/2″ sheetrock, paper-faced fiberglass between 2×4 16oc, 1/2″ ply sheathing, 1/4″ EPS, aluminum siding
I despise fiberglass insulation. The contractor who is doing the repairs asked me what I would like instead of fiberglass, but I’m not sure what to spec.
I’m in central NJ.
I would prefer 3.5″ foil faced polyiso. However, the thickest foil faced polyiso available in my area is 2″. I would sandwich two layers, but I worry about the double vapor barrier due to two layers of foil. No one seems to sell unfaced polyiso in my area.
I cannot do continuous foam because we’re not replacing the entire wall, so the width of the wall cannot change. All insulation needs to fit in the stud bay and I’ll have to live with the thermal bridging.
Would the following wall arrangement work?:
1/2″ sheetrock, 2″ foil faced polyiso btwn studs, 1.5″ unfaced XPS btwn studs, 1/2″ ply sheething, tar paper, house wrap, 1/4″ EPS, siding
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