How to Repair Cracked Sealant

Find out what to do if you notice that the sealant between your home’s brick front and vinyl siding is cracked. Learn why you can only caulk a 1/4-inch to 3/8-inch crack, and nothing larger than that.

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LESLIE: Jeff in Pennsylvania is dealing with cracked sealant between his brick front and vinyl siding. How can we help you today?

JEFF: Hi. I’m calling because I have a house that’s about 16 years old.

TOM: OK.

JEFF: And where the brick front matches up to the vinyl siding, the sealant is starting to crack. And I’m not sure if it’s caulk that’s drying out or mortar that’s just cracked. So, I guess the question is: what’s the right kind of sealant to put between that brick front and the vinyl siding?

TOM: Yeah, I’m sure it’s caulk because – you know, the caulk’s not going to last 16 years.

JEFF: Right.

TOM: So, what you need to do for this cracked sealant is to scrape out the old stuff and then recaulk it. And to do that, you’re just going to use a good-quality exterior caulk. I might suggest that you consider using silicone for this because that’s going to give you the best probably long-term durability. A little bit harder to use, Jeff, but it will last the longest.

JEFF: Now, I notice that the gap, in some places, is somewhere between half and a full inch. Do I need to put something behind it once I clean that?

TOM: Ooh, that’s huge. That’s really big. That’s not caulkable. You can only caulk with maybe a ¼ to 3/8-inch. Is that entire space filled up with some material now?

JEFF: Yes. And that’s – and it’s hard as a rock. That’s why I wondered if it was mortar behind the brick going into that.

TOM: Oh, it might not be caulk. I mean there are different types of urethane sealants and I can’t really be sure. Here’s what I suggest you do, Jeff. Would you take a photograph of this and post it in the Community section at MoneyPit.com? We’ll take a look at the cracked sealant and then get back to you with a recommendation. Does that make sense?

JEFF: OK. That’s great. I appreciate it.

TOM: Good luck with that project. Thanks so much for calling us at 888-MONEY-PIT.