Working on re-insulating the ceiling of the tucked-under garage on a 50 year old brick-veneered Cape Cod in the Philadelphia area. Ceiling demo was done earlier this week. On inspecting the rim areas I find that the 2×10 joists sit directly on the cement block wall with only some slate pieces under most ends, perhaps for leveling and alignment. There are no wood sills and no rim joists. Looking in, I am seeing the backs of the brick veneer with small piles of dropped mortar from the brick laying process. Overall, the bricks and mortar look fine. The joists end with about a 1″ gap to the bricks.
My intention had been to seal the rim areas with 2″ solid xps foam blocks sealed with Great Stuff Pro Gaps & Cracks foam. This will not sit well towards the outside of the foundation because of the mortar piles. I could back this assembly up closer to the mid-foundation position or to the inner foundation edge, but that would leave part or all of the joist ends in a potentially damp spot. Had thought about using closed cell spray foam, but current temperatures make that problematic. Then I listened to this week’s FHB podcast about insulating old brick houses and realized that I had better ask some questions before I proceed on my own.
Is there a best practice for this situation?