Exterior XPS sheathing over exterior 2x2 stud walls - good idea or not?
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I live in Michigan Zone 5a. I have an old Sears Craftsman house that has 2x2 stud walls with 1/4" plywood on the exterior for sheathing and on interior of the walls as the finish surface. The interior plywood has been painted over the years. It has steel frame windows with single glazing. Talk about cold and drafty. We are getting ready to install new windows and re-side with vinyl siding and would like to tighten the house and add a little R-value on the exterior when we do. We were going to install Tyvek over the exterior 1/4" plywood sheathing and then 3/4" XPS foam, then new windows and vinyl siding. We would love to do thicker foam but due to the roof details, we can only add the 3/4". I am not yet sure what, if any insulation is inside the wall, but if there is none, we could consider blowing them with cellulose.
With this thin wall assembly. are we setting ourselves up for moisture issues by adding the foam? Or is this little bit of R-value and thermal break a good idea?
Thank you, Joe
Posted Jan 30, 2013 9:28 AM ET
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