HELP! apprehensive about adding exterior XPS insulation
Hello everyone, this is my first post as an avid DIY homeowner. I have renovated multiple homes and I am a big fan of adding 2″ XPS insulation board to the exterior as part of a window and siding upgrade.
This “NEW” house just sent me a curve ball. I just discovered that my “NEW” 1982 home in upstate New York (zone 6) has 1/2″ foil faced polyiso between the studs and exterior sheathing.
I am very conflicted. Some say adding the 2″ XPS will prevent any condensation issues and not to worry about it, while others say that the sheathing will rot due to possible trapped moisture. I am inclined to add the XPS but I would like some more experience to chime in here.
My local code enforcement is a part time pencil pusher / rubber stamper with zero knowledge and even less interest in helping me find an answer. Thanks in advance.
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