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Posted: Aug 13, 2014 10:12 PM
spray foam onto rigid insulationI’m building a bungalow in the northern edge of climate zone 5, and I’m trying to decide on insulation for my main floor. The basement walls will get 2” R12 Walltite Eco spray foam, and the Rim Joist R20. My drawing calls for 1” R6.5 EnergyShield rigid insulation mounted directly on the 2x6 exterior main floor studs, then batts and poly in the bays. Instead of the batts and poly, I would like to do R20 Walltite spray foam with no interior VB and just drywall with latex paint. Is it okay to spray the inside face of the rigid insulation? I’m concerned about the heat when spraying, vapour permeability, as well as the possible double VB. I’m assuming this type of wall would need to dry to the inside.
There will be a 1” air gap before the brick finish. I would like to go with a thicker exterior foam, but the windows have already been ordered and I’m told this can’t be changed. I realize this is a spray foam forum, but does anyone know if a house wrap should be used on the outside of the rigid foam board for extra weather protection?