Heaving on a new cement patio?

Old 02-15-07, 11:33 AM
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Question Heaving on a new cement patio?

I built a new home last summer in MI and poured a cement slab under the deck. The slab is outside a slider door on the basement level (ranch with a walk-out). The slab has heaved an estimated 3-4 inches and is now above the slider opening. This has started to take one of the deck posts up with it and has raised the deck in that spot an estimated 1/4 to 1/2 inch.

The slab has not cracked. Is it reasonable to believe that the slab will go back down to where it should be in the spring? If so, will it likely heave again next winter?

What do you suggest to solve this issue?


Old 02-15-07, 12:20 PM
Join Date: Mar 2005
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Heaving on a new cement patio?

It will probably go down some.

It will probably come up again.

You have poor soil (clay, silt, organics, dirt, etc.) under the slab with poor drainage. When the soil gets saturated and form ice lenses, the soil will heave.

Getting rid of the moisture with proper drainage and gutter downspout extensions may help. The other option is replacement.

Your deck posts may not be deep enough. The concrete footing should be below frost for your area. If you are a "flat lander" that is probably 42" or so, if you are north, it will be more.

It will be waiting game since this is probably your first winter.


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