Repair Cracks in a Concrete Slab
LESLIE: Rocky in Florida listens on WGUF. What can we do for you today?
ROCKY: My sister just bought a mobile home. She’s got a solid concrete slab in her driveway. It’s cracking. And it looks like the previous owner may have used some sort of silicone or something and she’s got some major cracks in it. How do I fix it for her?
TOM: Well, you know, a silicone caulk – a good quality silicone caulk – is the right way to repair those cracks. The other option is something called flowable urethane, which is sort of a low-viscosity urethane caulk that’s used where you have wider gaps. The fact that the concrete is cracking is not unusual. It’s going to crack; mostly because those driveways are never put down with the proper reinforcement. So you kind of live with the cracks to the point where it displaces and becomes a tripping hazard and otherwise is unsafe. Otherwise, you simply keep repairing the cracks. The goal here is to try to keep as much water out of it as possible, Rocky, because when water gets into the cracks, it weakens the soil underneath the slab and that’s what makes it move as you drive your car over it.
ROCKY: It’s under a carport and they’re – the cracks are probably a good quarter-inch.
TOM: That’s not too bad. Yeah, I know it sounds like a lot but it’s really not that unusual. I would continue to use silicone or a flowable urethane on that. You know, the only other option is to replace it and I just don’t think it’s worth it.