Cracks in Slab House Walls and Floors: Signs of Structural Problems?

LESLIE: Erin in Louisiana is on the line and seeing cracks in slab house walls and floors. How can we help you today?

ERIN: Hi. I have a slab house that’s about 35 years old and it’s showing signs of needing to be leveled. But I thought I heard on a previous show of yours that you do not recommend leveling a house; just fix the issues that come up as it needs it. And I didn’t know if I heard correctly or not, so I thought I would call and ask about that.

LESLIE: Well, tell me, how much of a slope are you noticing, throughout the property, on the interior of the home?

ERIN: No, we’re seeing cracks in the walls, cracks in the ceiling, cracks in the floors.

LESLIE: OK. Now, if you put a marble on the floor in some of these rooms that you’re seeing these cracks, does it roll all around wildly? If it does roll, how fast?

ERIN: I actually have not done anything like that.

LESLIE: Ah, the marble test. It’s very fun. That will tell you if the ground itself is level.

Now, if you’re seeing cracks in slab house walls and in the ceiling, are they sort of near a doorway or a window or are they just square in the middle of stuff?

ERIN: Well, there’s a crack in the floor that’s square in the middle of the floor and it extends out into a – we have a sliding-glass door and the brick above the sliding-glass door is separated. Then, we also see it – I also see it in rooms next to the wall, where it’s like – the house is shaped like a T. And where one part of the top of the T goes into the long part of the T, I can see it separating there against the – in the ceiling.

LESLIE: Generally, if you see cracks in slab house walls and they’re by a doorframe or a window, that’s just general movement because of the opening in the envelope of the home, being in a window opening or a doorway in an interior wall. Now, if you’re seeing it like in the middle of the floor and above a doorframe in brick, you might be concerned that there could be some structural issues going on. However, you might want to bring in a structural engineer.

You bring in an engineer or even a home inspector and for a couple of hundred bucks, they’ll come in and look at these areas and diagnose, specifically, what’s going on there. Because it could be something structural that could need to be fixed in a way that you can’t just do by repairing the crack. Or it could just simply be natural settlement of the home over the duration of the home’s lifespan and that’s easily fixable.

But because you have a crack forming in the middle of a floor and that continues to a doorway, I would definitely bring in somebody who’s a structural engineer and they can write up a report on it. And the benefit of doing that is that when you do fix this, whatever the problem may be, you are going to have a full, written pedigree of what you’ve done to the problem in the home, how you’ve fixed it and what everything was done correctly. This way, if you go to sell the home and somebody says, “Oh, I saw a crack,” or whatever the situation might be, you can say, “Actually, this happened. We did this repair and it’s all square.”

ERIN: OK.

TOM: Erin, some cracks are really typical wear and tear, so to speak. But this one definitely sounds like you need a pro to check it out. Thanks so much for calling us at 888-MONEY-PIT.