It’s been maybe a low of 32 here recently but our house has been cold and the furnace has been running almost non-stop it seems. From what I’m reading online, apparently rim joists being uninsulated (or underinsulated) are one of the first areas to address.
In our basement, we currently have old fiberglass insulation in maybe 3/4 of the rim joist pockets which is certainly better than nothing (I think).
There are a total of 58 rim joists I need to insulate. Each are approximately 15” W x 9.5” H.
I’ve been reading quite a bit about the best way to insulate these and it seems there are two paths forward:
- Spray foam the pockets (DAP Touch ‘N Foam Wall & Cavity - 2 canister mixture)
- Pros: easy to do, blocks insects, best R value
- Cons: expensive, messy, near permanent (issue if I need to do work behind)
- Rigid foam board w/ foam gap filler on edges & existing fiberglass insulation on top
- Pros: affordable, can be taken down if needed, cleaner to install, allows re-use of already used materials, blocks insects
- Cons: Lower R value than spray foam
I’m thinking of going with option 2 above, but still debating. I just wanted to get my thoughts down. I think I’ll come back here and add some photos of the current state, and updated once I get around to doing it.
Here’s some good youtube videos on the process: