I am planning on installing 2" XPS foam board directly to my basement wall, which is cinder block and continues all the way up to the 2nd story. I am using the recommendations from Building Science when framing out the wall. However, I am hearing of people having problems with inspectors telling them the you need a fire stop that goes through the XPS to the wall, which contradicts what Building Science says to do, which is XPS from floor to ceiling. How do you provide firestop in this situation when using XPS as a vapor barrier against a cinder block basement wall?