Should I insulate the interior side of the basement wall if there is already XPS on the outside?
I have an unfinished basement in N.E. Ohio. Uninsulated slab floor with poly vapor barrier underneath. 13 course block walls with 2″ XPS foam on the exterior side. We are looking into finishing the space for a guest room/suite with a bathroom, excercise area, office and family room/play space. Being that there is already r-10 on the outside of the walls will adding a layer of 2″ XPS (r-10) create any problems? I have been reading everything Ican find on GBA and Building Science but everything seems to refer to either or, not both.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part