How to Seal a Cracked Concrete Driveway
LESLIE: Janice in New Jersey is talking about cracks in the driveway.
JANICE: Yes. Oh, a little bit upsetting. I have a concrete driveway and after a near-record rainfall all through the month of October, I’ve noticed that there were cracks that have developed all the way across the width of the driveway. We did have – I don’t know whether this has anything to do with it – before this record rainfall we had an extremely hot and dry August and September. So now these cracks are really pretty disturbing and I’m wondering what I should do about it. I’m hoping it’s not a case where I have to take the whole driveway up and replace it.
TOM: Well, how old is this driveway, Janice?
JANICE: That I don’t know. I moved into this house this past summer.
TOM: Is it a newer house or …?
JANICE: It was built in the 50s.
TOM: OK. Well, you’re not going to be able to repair the cracks. I mean you’re never going to put the concrete back together again. The best you can do is to caulk them. I would use a flowable urethane caulk with those cracks; available at home centers. And basically, you’re filling them in with a caulk that’s similar in color.
The fact that you did have an incredibly hot summer means that the earth was very, very dry; coupled with a very …
LESLIE: And then all that water caused it to shift, which caused the cracks.
LESLIE: Like things were settling and moving.
TOM: Yeah. And once that water gets under those slabs, then it just kind of slides down the hill, so to speak. Now if the driveway is put in with expansion and contraction joints, that won’t happen but this driveway was not done that way and that’s why you’ve got that movement. So the best you can do right now is just to seal those cracks and you’re doing that for cosmetics; you’re also doing it so that you prevent the water from getting into those cracks and further separating the spots. Because if the water gets in there and then in the wintertime it freezes, it’ll push those slabs apart. Even though they’re big and heavy slabs of concrete, it’ll actually push them apart or the water can get under it and push them up and cause what’s called a frost heave and that’s a big, stinking mess, too. So the best thing for you to do is to simply seal it up with caulk.
JANICE: OK. And just make sure that it’s level? Is there – should you use something like those tools that level out the cement when you’re doing concrete or cement work?
TOM: Well, you’re kind of past that now because the concrete is already there and in and dry and hard, so all you’re trying to do is just seal it. Now if the slabs start to lift, then that’s a different problem and we can talk about that a different time. But if you’re just talking about a section that is just cracked, then all you need to do is to fill that in with a flowable urethane caulk and just maintain it that way. OK?
JANICE: OK, thank you.
TOM: You’re welcome. Thanks so much for calling us at 888-MONEY-PIT.