Alternatives to spray foam

[RWiebking]

I'm trying to insulate the crawl space under my kitchen. It's small and a bit damp, and I need to reach R10. I usually use spray foam, but I want something cleaner and easier to put in. Has anyone used solid boards like mineral wool or anything else that can stay uncovered? I want to know if they last long and still look okay in a space like this. Thanks for any help!

 

[furg0y]

Rigid foam boards are good for damp crawl spaces since they handle moisture better than mineral wool. They'll hold up fine uncovered if you cut and fit them tight, and you can tape the seams to keep things neat. Just make sure you address the dampness first so you're not trapping moisture

 

[RosalieGomez03]

To handle a damp crawl space, fix the water problem and add some insulation. You might want to use a vapor barrier and get some air flowing in there

 

[slvr22_bd]

I'm trying to insulate the crawl space under my kitchen. It's small and a bit damp, and I need to reach R10. I usually use spray foam, but I want something cleaner and easier to put in. Has anyone used solid boards like mineral wool or anything else that can stay uncovered? I want to know if they last long and still look okay in a space like this. Thanks for any help!

I agree with @RosalieGomez03 about fixing the drainage issue first. The best insulation in the world won't matter if you've got standing water. Once that's handled, I'd still stick with XPS foam boards. The mineral wool can get heavy and saggy if there's any moisture. A 2-inch XPS board will get you your R10 and it's practically waterproof, so you don't have to worry about it degrading. The install is super clean too. Just cut it to fit and seal the seams with foil tape. It's a much better, more durable solution for a small, damp space.

 

[ne0nhorse]

I agree with @RosalieGomez03 about fixing the drainage issue first. The best insulation in the world won't matter if you've got standing water. Once that's handled, I'd still stick with XPS foam boards. The mineral wool can get heavy and saggy if there's any moisture. A 2-inch XPS board will get you your R10 and it's practically waterproof, so you don't have to worry about it degrading. The install is super clean too. Just cut it to fit and seal the seams with foil tape. It's a much better, more durable solution for a small, damp space.

Thanks for the tip! I'm fixing up a small laundry room that gets damp during heavy rains, pretty sure drainage's the first thing I need to focus on. XPS sounds solid for that kind of space.

I have a question though, does XPS work okay if the walls aren't perfectly flat? And is foil tape enough to seal it, or should I use something else around the edges? Just trying to plan ahead.

 

[slvr22_bd]

XPS works fine on uneven walls, but since it's rigid, you might have small gaps behind it. A few dabs of construction adhesive on the high spots will help bridge the gaps and hold the board in place. You can use foil tape to seal the seams between the boards, but where the board meets the wall, use a bead of low-expanding spray foam to create a complete air barrier. It's a much more durable seal than tape at those edges.