Prevent Water from Rising Through a Concrete Garage Floor

Irene in Ohio, what can we do for you?

IRENE: Well, my husband decided to build the garage mahal in our yard last year. (chuckling)

TOM: The garage mahal (chuckling). OK.

IRENE: (chuckling) And – it has earned its name. It is 24×40 feet.

TOM: Wow.

LESLIE: Oh, my God (laughing).

IRENE: Yeah. (chuckling) The concrete – we live in an area with a high water table and I know concrete is porous and they – the contractor poured the concrete. Did come back and seal it. But we are having water, actually, coming up through the concrete …

TOM: Hmm.

IRENE: … in the garage when we get times of heavy rain. And I need to know what to do about it.

TOM: Usually, that’s a drainage problem, Irene. The water table’s not as high as grade. Because I presume that the garage concrete floor is on top of grade, right?

IRENE: Yes, it is.

TOM: It’s not buried – it’s not – it’s not subterranean in any way, is it?

IRENE: No, no. It is above the grade.

TOM: OK. So, generally what happens is you have a poor drainage problem somewhere in the foundation perimeter and water actually pushes under that concrete slab and it will go actually some number of feet in and then sort of push up. So it’s just the pressure of the water collecting on the outside, pushing down and up. So you need to look at the drainage conditions.

Does your husband have gutters on the garage mahal? (laughter)

IRENE: Not yet.

TOM: Well, that’s part of your problem right there.

IRENE: We’re still finishing the siding on it (chuckling).

TOM: Yeah, you need to order garage mahal gutters (chuckling) and then you need to order garage mahal grading so that the soil slopes away from the wall. If you have no gutters and you have no grading on this, that slopes the water away, the water will do strange things like push under the wall and come on up into the middle of the garage.

LESLIE: And make sure those downspouts on that new gutter system you’re going to put in go pretty far away from the house – from the garage mahal – excuse me – you know three feet or so.

TOM: And that will – that will – that will shut down the garage mahal geyser (chuckling) that you have right now.

Alright, Irene.

LESLIE: (chuckling) That is a huge garage.

TOM: Thanks so much for calling us at 888-MONEY-PIT.