Can continuous insulation be installed to the inside in a cold climate?
I am working with some builders trying to achieve ENERGY STAR v3 on existing homes. These are structural brick homes (12″). The exterior walls were all framed out with 2×4. The builder wants to put r5 continuous to the inside and then dense pack or wet apply cellulose in the cavity with the cellulose being I contact with the structural brick. I don’t like this approach and recommended that they either take down the framing and insulate the structural masonry wall to the IECC minimum for mass walls of R17 directly adjacent to the brick (rigid foam board with seams taped in order to not violate historical preservation) or insulate to r5 cont. against the brick and frame out the wall to the inside of the foam board and then insulate to at minimum to r13 with whatever you want as long as it meets RESNET GII.the only other scenario I would even consider, and that was on the condition that I can get it on some valid authority, would be to somehow install some air barrier material to the backside of the framing adjacent to the brick (15# builder paper, tyvek, the builder suggested 1/4 inch foam) then insulate to r13 with r5 cont. to the inside adjacent to the conditioned space. It would be an air tight assembly so the cellulose or any fibrous insulation would have a better chance of performing, but I don’t know if it would work in Climate zone 5. Is this a decent strategy?
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