Wide, Deep Crack in Concrete Porch: How to Fix
LESLIE: Now we’ve got Ann on The Money Pit who’s got a question about a porch. How can we help you today?
ANN: Our front porch, I guess, has settled. And there’s a huge crack and it goes completely through the whole slab of concrete. How would we go about economically fixing that or is it possible without having to repour the whole thing? And it’s like a slab on top of bricks, so there is a hollow spot underneath the slab.
TOM: OK. So it’s broken in two? And can you see through the crack into the sort of the void below?
ANN: You can’t exactly see through but it is a wide crack. It’s wide enough to see. Not all the way through, though.
TOM: What you would do is if it’s wide enough where it’s not going to hold a patching material, you would put something in there first called “backer rod,” which is like a foam road. And it comes in different diameters. And that would sit just below the surface of the crack, maybe a ¼- to ½-inch below the surface of the crack. And then you would repair that crack with a flowable caulk, like a flowable urethane? Or I know that QUIKRETE has some patching materials that will also work.
And that backer rod keeps that seal up towards the surface – does that make sense? – and doesn’t fall down in. So it’s not like you’ve got to put coat after coat after coat. And that flowable urethane will expand and contract with the concrete slab. So you don’t have to tear it out and replace it; you just have to fix it correctly.