Adding XPS insulation
Question about adding rigid XPS foam to my house. I am in zone 5, and my home was built in 1988. The wall system consists of 2×4 framed walls with 1/2 inch XPS foam as the exterior sheathing. The builder insulated the 2×4 bays with an R13 paper faced fiberglass batt insulation, with the facing on the inside of the wall system.
I have done a number of renovations and never noticed any issues with moisture, but I wanted to ask if I may introduce moisture issues if I add an additional 1.5 inch layer of XPS insulation on the exterior when replacing a section of siding?
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