Don’t Use Foam Filler to Replace Brick Mortar

LESLIE: Jason in Texas is calling us with a crafty painting project. Tell us what’s going on.

JASON: Yes, I’m getting ready to paint my 80-year-old brick house. And I’ve heard of filling the mortar joints with epoxy but I was wondering if you’ve ever heard about anybody using the – like the foam filler to fill the cracks with.

TOM: Now, are you talking about mortar that’s become loose and deteriorated in this 80-year-old brick?

JASON: Exactly. And it’s – I can tell it’s old stuff that people have already tried to repair, that I’m going to have to take out.

TOM: Well and that would be an enormous mistake because as good as GREAT STUFF is and other types of expandable foam fillers, it’s not a replacement for mortar.

JASON: OK.

TOM: OK? So you have to do this right. You have to scrape out the loose, deteriorated mortar, you have to mix up new mortar and then trowel it back in place. It’s not an expensive job if you do it yourself but it’s not simple, in the sense that it takes some time and some patience.

JASON: Right. Have you heard of filling it with the concrete crack filler?

TOM: Well, what you want is simply mortar mix.

JASON: Do I need to mix that with lime? Have you ever heard of that? People mixing that with lime?

TOM: Yeah, yes and – right. And did you know the reason that people do that? They do it to make it stickier. To make the mix stickier.

JASON: Oh, OK.

TOM: If you’re going to make your own mortar, you mix up concrete and you put a lot of lime in there and it makes it sticky. But if you buy the premixed mortar mix, it’s pretty good as is.

And the other thing that you’re going to need is something called a pointing trowel, which is a very skinny trowel that gives you sort of that curved, concave joint in the bricks.

JASON: Yeah but – right, right. Alright. Well, I appreciate it. So don’t use the foam filler then to fill the …

LESLIE: No. Because it’s not going to take the paint correctly. It grows quite exponentially and you can’t really control that and it’s going to seem wonky.

JASON: Right.

TOM: In fact, I know that QUIKRETE has a new product out, Jason, that’s called Zip & Mix Repair Mortar, where it actually comes inside of a plastic bag. And all you’ve got to do is to add water and sort of knead it inside the bag and it even has a trowel.

JASON: Alright. Well, thank you very much.

TOM: You’re welcome, Jason. Thanks so much for calling us at 888-MONEY-PIT.