How do we keep a concrete patio from sinking and cracking?
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Teacher
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We have replaced our patio twice. Each time it lasts for a while but eventualy settles and cracks. We have tried building up the soil etc underneath. We would like to replace it but are afraid that it will just do this again. The original patio was installed 50 years ago and replaced 20 years ago. How do we fix cracks in the concrete patio and keep it from sinking?
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My best guess is that the soil was never properly compacted and your water table is high. How is drainage in the area? If it were me, I would have a consult with a soils engineer to see what they suggest.
Techniques have changed over the years and have gotten better. 50 and 20 years is great longevity. Only thing you can do is have it replaced. Modern concrete mixes and techniques make for better and lasting pours.
We had a similar problem and got a core sample done. They discovered that we have vegetation about 11 feet underground. They suggested "mud-jacking" it.. They bore holes in the existing concrete and inject more concrete underneath to raise it up. Cheaper than total replacement by approx. half.. Larger areas and foundation might need underpinning.. Which is a different process, but lifts it to the level it should be.
What prep was done underneath it? was a area cut down into the earth, gravel layer tamped down then a layer of sand added, tamped and leveled, a form added and then a metal grid added? If its a large slab were expansion joints added? Did you seal the concrete once it was cured, and done every other year? Did you maintain and repair any cracks and spauling to prevent the concrete from breaking down? All these things contribute to your slab lasting.
the only thing constant about concrete is that it will crack maybe consider pavers with grass in between. If you give up on the concrete. They are more forgiving.
You’re not in Texas, but very few homes around Dallas have foundations that don’t eventually crack, break or separate. And a concrete patio is not as thick, does not use a pier-and-beam or bedrock foundation, and often does not use a gravel bed before it is poured. Whether the patio is built by pros or amateurs, it’s going to give way at some point. You can bust it all and remove it and do it all over properly, or consider a low wooden deck with the patio keeping the gophers out. Best wishes ☺️
Here in the midwest they put metal rebar in cement driveways...would that work on a patio? I am just asking...not sure.