Insulate Box Beam to Warm Up Chilly Basement

Find out if it's OK to insulate a gap between your home's exterior and stud walls that opens into your basement and dumps cold air into it. Learn why that is actually a standard place to add insulation — it's…

LESLIE: Now we’ve got Dean in Pennsylvania on the line who wants to insulate box beam. What can we do for you today?

DEAN: I have an older home. It has a brick exterior and then the stud walls on the inside. And between there is the air space. And that air space, it dumps down in the basement. And in the wintertime, I’m feeling the cold air sinking and I want to try and get my kids to use the basement a little bit more but it’s a little on the chilly side. And I don’t know if I’m – if that’s like a vent of some sort, if I’m allowed to insulate that or will I cause problems if I close it off or what?

TOM: You can actually see where this gap opens up to the basement?

DEAN: Yep, mm-hmm.

TOM: There’s no reason that you can’t insulate that. That would be along what we call the “box beam” or the “box insulation.” And that’s actually a standard place to add insulation.

The other thing that you could consider doing to insulate box beam is you could use an expandable foam in that area to kind of seal the gap, if it’s not too wide, or simply add some fiberglass-batt insulation there. I think that’s the easiest thing to do. That will stop some of that draft from getting through to the basement and make being down there a lot more comfortable.

DEAN: Yeah, right. I didn’t know if that was how you have insulated windows now: two panes of glass with the air space in between. I didn’t know if it was something like that.

TOM: No, there’s not quite that much thought put into it. It’s just kind of the way those old homes were built. So you can certainly insulate that space.

DEAN: Awesome. That’ll do.

TOM: Alright. Well, we’re glad we could help. 888-666-3974.