Repair Crumbling Brick Chimney
LESLIE: Well, Chris in Virginia has a crumbling problem. What’s going on? The brick on the outside of your house is falling apart?
CHRIS: Yes, I … I have a house that was built in about 1964 and for some reason a lot of the bricks, especially on the chimney, just appear to be crumbling apart. And I thought it was kind of odd since most of the brick houses I’ve seen last a long time.
LESLIE: And that’s the only area that you’re seeing this problem.
CHRIS: More so on the chimney. And occasionally, around the foundation. And I’m wondering if it’s a cosmetic issue I should not worry about. If it’s something that’s serious; needs to be replaced.
LESLIE: How are the bricks crumbling? Is it at the corners? Is it in the center? Is it a line?
TOM: And is it the bricks themselves? Or is it the mortar that’s crumbling?
CHRIS: No, it’s definitely the bricks.
CHRIS: Mortar’s fine. But the actual integrity of the brick – the front, it comes off in sheets almost.
TOM: Mm-hmm. Is it mostly near where the ground connects?
CHRIS: There’s some that are down near the ground and then the rest are on the chimney.
TOM: Right. Well, that’s called spalling. And it happens when the bricks get wet and then they freeze and then they sort of break apart.
LESLIE: Ooh, it’s almost like an ice damming for your bricks.
TOM: Mmm, sort of. Sort of. It sort of just splits off. It’s … structurally, you could probably lose a half-inch of the brick surface and it’s not going to have any impact on it. Typically, it happens where the mortar joints are recessed. The water soaks in there and then cracks off. I mean can you patch it? Can you replace the brick? Sure. But unless it gets really bad, it’s probably not worth it. More common condition is where the mortar dries out and falls out and that’s called repointing. So if it’s … it’s mostly on the chimney that you’re concerned about this, Chris?
CHRIS: That’s correct.
TOM: Yeah. I would not worry too much about it unless you really lose a lot of brick and if that’s the case, you’re going to have to rebuild it and replace those bricks.
CHRIS: Alright, thank you very much.
TOM: You’re welcome. Thanks so much for calling us at 888-MONEY-PIT. And you know, Leslie, a good way to slow that process down is to make sure that there’s no water getting in the top of the chimney.
TOM: Between the (inaudible).
LESLIE: So would that be like a chimney cap?
TOM: Yeah, a chimney cap is good. And also, if you have a clay flue liner that goes up through the middle of the chimney. Then you have like a concrete lip that goes between the flue liner and the edge of the brick. Make sure that concrete cap doesn’t have any cracks, any holes in it or is missing. Because if you can keep the water from getting sort of behind the brick, that will actually help protect the integrity of the brick as well.
LESLIE: Now, what about the ones in the foundation for him? Do you think that’s a moisture problem and he should look at his grading?
TOM: Yeah, you know what happens? What happens there is the rain splashes up. And that’s a matter of controlling the drainage the same way you control it for any other kind of drainage issue; trying to keep the water away from that. But that’s just the way that old brick wears. It’s going to … it’s going to get wet and it’s going to freeze and it’s going to spall and break off.
LESLIE: Oh, but it looks so pretty.
TOM: It does look pretty. You could seal it but if you’re going to use a brick sealer on it, you want to use one that is vapor permeable so that the moisture can evaporate out. That will slow some of the water –
LESLIE: (overlapping) And doesn’t get trapped in.
TOM: Yeah, that will slow some of the water from soaking in and slow down the process a little bit. But make sure you use a sealer that’s vapor permeable. If you try to seal the water in, it doesn’t seal in; the water still gets in there and then the cracking gets even worse.