I have a 40 yr old single story modular home set on a block foundation. I used a thermal temperature gun to verify a temperature difference. the insulated wall is approximately 1 to 2 degrees cooler than the room ambient. I consider that normal with 6” exterior stud walls. Problem is I’m finding at the baseboards the temperature to be 10 to 12 degrees colder than room ambient. (Typically when outside temp. is below freezing) This is attributed to cold air transferring into the home.
The interior floor joists are well insulated in the basement. I removed and inspected a few locations but find no gaps to exterior. Typical interior insulation as current is as shown in this photo.
Investigating the exterior, i find there is a 1/2” gap between the rim joist and the original exterior lap siding. You will note in the photo a metal siding was applied over the original vertical lap siding.
In the photo, you can see the gap which had what appears to be a foam rubber type insulation. Appears this foam rubber insulation has fallen out or disintegrated over time. Even vermin of some type or field mice could be the cause.
I have the original construction drawings and included two copies of the detail. It does not indicate any type of insulation within this area. Yet the gap between the rim joist or so called Sill Band exists all around the house perimeter on exterior.
My question is could I use a spray foam to fill in this gap? I was thinking maybe Great-Stuff window and Door spray foam would be a good choice. If an alternate would be advised, please advise? Especially since the spray foam would be difficult to remove after the application. Yet may be the best deterrent to mice, etc.
I do not foresee moisture being trapped, as metal siding would provide the shedding any rainfall, etc.
- Follow up for clarification: Appreciate any thoughts. I am not concerned with risks for cleanup using spray foam. The picture provided is the only side of house you can actually see the gap. It is on the one side with garage doors. (Garage is part of the basement.) The rest of the house siding is only about 6” above grade. Would be very difficult to manually pack the other 3 sides of the house. Would almost need a mirror and go by feel to find the gap. That is why I am considering spray foam.
Would spray foam be a concern for trapping moisture between the rim joist and exterior sheeting? Also I have used spray foam before and worked well to stop rodents. Not bullet proof, but certainly is a good deterrent.