I'm insulating a closet on an exterior wall using ISO foam boards glued in place. However, since the boards come in pieces, there are some small gaps between them and at the borders. I was wondering if I can use regular spray foam to fill these gaps, allow it to dry, and then trim any excess off with a utility knife. I'm a bit concerned about the force spray foam might exert on the boards, especially since I've heard there are issues with spray foam around windows. Any advice?
3 Answers
Definitely use spray foam! I find it works best if you leave a bit of a gap, like around 3/8 to 1/2 inch. It makes it much easier to fill. Just remember to cap it off with some foil tape for a nice finish!
There are specific sealing tapes available that work well for seams, often in red. But yeah, using foam is totally fine too. Just keep in mind to seal the bottom properly!
Yeah, you should be good to go with that! Just make sure to apply the spray foam carefully, and it shouldn't cause any issues with your ISO boards. If you're planning to insulate further, some people also recommend using foil tape for finishing touches.