What Causes Concrete Settlement?

Summer is almost here and that means perfect patio weather.  Are you constantly tripping over your uneven patio, or wearing out car tires on your unlevel driveway or garage floor? Underlying soil issues are likely the culprit for your settling concrete. 

Concrete slab settlement is most common in stoops, patios, sidewalks, and driveways. Where the distance between the concrete slab and underlying soil is minimal. Because the distance is shorter, the floor slab is easily influenced by the soil underneath. 

There are four main causes for floor slab settlement. 

Clay soil is at the heart of this issue. Often ductwork for heating, ventilating, and air conditioning are installed beneath the floor slab. Over periods of time it is not uncommon for that ductwork to leak air and dry out the soil underneath the slab. When the soil dries and shrinks, gaps form between the slab and the soil creating a void. This void makes it impossible for the soil to support the floor slab, causing the floor to crack and sink into the void.  

Washout is often caused by plumbing leaks. If the leak is severe enough and there is a path for the water to flow freely it can was out the soil underneath the slab. This also creates a void rendering the soil ineffective when supporting the floor slab. Similar to number one, the slab sinks and cracks into the empty space of the void.  

When a new home is being constructed, layers of soil are moved around or spread out at a desired grade level. Footings may be deepened to extend below weak layers of soil. But there is nothing to be done about the slab – still resting on fill soils. If the fill soil was poorly compacted, it compresses and settles. This also creates a void under the slab once again causing the slab to sink, crack, and settle.  

Heave is the upward movement of a foundation or slab caused by expanding and swelling of the underlying clay soil caused by an increase of moisture. After a home is built, the moisture levels of dry soils below interior slabs will naturally increase. The increase in moisture causes clay soil to expand pressure on the slab is increased forcing the slab upward along with interior partition walls and floors.  

It is more enjoyable to relax on an level patio, or avoid tripping over cracks in your driveway and sidewalks when you're trying to enjoy all the summer fun. Midwest Basement Systems offers a variety of concrete leveling solutions to help you fend off concrete settlement. Our PolyLEVEL technology is an industry leading solution for dealing with the eye-sores like settling driveways, sidewalks, patios, stoops, and more!