Install Tile Over a Cracked Concrete Floor
LESLIE: Thomas in New Mexico, what can we do for you?
THOMAS: Hi. I’ve got a home here. It sits on a concrete slab or concrete pad. And took the living room carpet out, oh, about two, three weeks ago. And that covers about half of the width of the house. And I notice there’s a crack that goes from one wall, across the floor and it looks like it continues on, probably all the way to the other side of the house. And I’m wondering, I want to put tile in that room and I’m wondering if I need to grind that crack out and fill it and if so, what should I fill it with? Or should I not even worry about it?
TOM: Not likely. It’s fairly common to have cracks in concrete slabs. And of course, they come to your attention when you, you know, remove the carpet and can see them.
LESLIE: But most of the time, they’ve occurred in the first few years after the home was built – right? – and don’t generally change.
TOM: Yeah, generally they’re not – I would bring it to the attention of the – are you going to put the tile in yourself?
THOMAS: Yes, uh-huh.
TOM: Well, what you might want to do is make sure you put a bit of a mud base under that. That will give you some ability for the floor and the tile to move independently of each other. There’s an underlayment that can go on top of the floor and under the tile that will create sort of like an expansion joint. So if the floor does move, it’s not going to pull the tile apart as well.
THOMAS: OK. That’s different than the mortar or is that the same?
TOM: Yeah. Yeah, there’s actually a – it’s not rubber, but it looks like that. It’s like a …
LESLIE: Is it that orange, woven mesh stuff?
TOM: Yeah. Yeah, exactly.
LESLIE: It almost acts as a rigidity system to this mud flooring that you’re going to put on …
LESLIE: … which allows you to put on far less than you would if you were pouring a straight mud floor to go on, with some tiling.
TOM: And if that floor decides to expand and contract after it’s up, I’m concerned that it doesn’t pull your tile joint apart.
LESLIE: Yeah. Because if you go right on top of that concrete pad, as it moves, you’re going to crack your tiles; you’re going to crack your everything. It’s just going to be a mess.
THOMAS: Oh, OK. And you can get this mesh at any kind of hardware store?
TOM: Any home center. Yep. Or a tile supply house would have it.