Beefing Up Insufficient Flash-and-Batt Insulation
House is 15 years old in zone 6 (northern NY state). Builder used flash and batt in the walls. Noticed some water stains on an unfinished (osb) floor in a loft area. Opened wall and found only 1/2 inch of flash on exterior wall sheeting with unfaced R19 batts with poly stapled up but slit open behind sheet rock. Can I replace poly with certainteeds membrain and have a workable system that will prevent condensation on the flash in the wall cavity? Or is the only option to apply a couple inches of spray foam? Then install less batt fiberglass?
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