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Concrete raising durring winter freeze

by Justin
(Saginaw, MI)

Q. I have a concrete driveway, and patio in the back. Inevitably, every winter, water will get underneath, freeze, and raise the concrete up a few inches along a side or at a corner.

What causes this (besides frozen water), was it not poured properly?

More importantly, what can I do to prevent/fix the problem?


A. The reason this happens has nothing to do with how the concrete was poured, but how the subgrade was prepared. Obviously water pools underneath, but usually there's not much you can do about that without taking out the concrete to fix the subgrade. The only thing you can do to alleviate the problem is divert any water going underneath. Caulk any cracks, caulk along any walls, and use downspout extensions to divert all that water coming from the roof. Do whatever you can do to prevent unnecessary water from getting under the concrete.