3 Main Causes of Sinking Concrete
When the soil underneath can’t hold up the weight of your concrete slab anymore, things start to shift—and not in a good way.
Concrete sinking can be a real headache, whether it’s your driveway, walkway, or even your garage floor. When the soil underneath can’t hold up the weight of your concrete slab anymore, things start to shift—and not in a good way. Here are the three biggest reasons why this happens:
1. Soil Washout Beneath Concrete Slabs
Water is a sneaky troublemaker when it comes to sinking concrete. When water gets into the soil beneath your concrete (think walkways, pool decks, or basement floors), it can wash away the soil, leaving empty spaces where solid ground should be. With nothing solid to support it, the concrete starts to sink, leading to uneven surfaces and potential trip hazards.
The fix? Deal with water issues ASAP. Whether it’s repairing plumbing leaks, upgrading your drainage system, or just making sure water isn’t pooling where it shouldn’t be, taking care of the water problem can help keep your concrete right where it belongs.
2. Poorly Compacted Fill Soil
When concrete is first laid, the soil underneath needs to be tightly packed to give it a solid foundation. But if the soil wasn’t compacted properly during construction, it can cause problems down the road. Loose soil tends to settle over time, creating gaps under the concrete. And when that happens, the concrete starts to sink into those voids, especially around the edges and corners where the support is weakest.
Not only does this make your concrete look uneven, but it also puts extra stress on the slab, which can lead to cracks and other damage. And when one section of concrete sinks, it can mess with the surrounding slabs too, causing even more issues.
3. Soil Moisture Content Changes
Mother Nature also plays a big role in concrete sinking, especially if you’ve got clay-heavy soil. Clay loves to hold onto water, so when there’s a lot of rain or heavy watering, the soil swells up. This extra pressure can push against the underside of your concrete, and once things dry out, the soil shrinks back down, leaving empty spaces behind.
This cycle of wetting and drying is like a slow-motion tug-of-war on your concrete. Over time, all that expanding and shrinking leads to more voids under the slab, which eventually causes it to crack, sink, or both.
In short, keeping an eye on soil moisture levels and managing water around your home can go a long way in preventing your concrete from sinking. A little attention now can save you from big repairs later!
