What Causes Soil to Shift?

Soil bows to the whims of nature. Our area has seen many wild weather events, including thunderstorms, tornadoes, and earthquakes. All of these can impact your home and patio by affecting the soil. 

Flooding 

Soil suffers greatly from water, but especially from flooding events. Flooding causes soil to swell with water and loosen, allowing it to erode over time. Given enough time, this will hollow out a cavity beneath the concrete slab. 

Alternatively, flooding can soften the soil to the point where the weight of the slab forces the muddy earth to ooze out from beneath it. Waterlogged soil can even cause the slab to sink. 

Water can apply more force to the earth supporting your patio than many realize! 

Thawing 

As the soil freezes and thaws over the seasons and many years, small shifts in the soil can also develop and cause sinking. This is a weathering process where the soil passes through cycles of shrinking as it dries and expanding as it freezes. 

Waterlogged soil will see a much more rapidly developed impact of freezing and thawing, as there is more moisture that will develop ice crystals. These crystals are what push the soil particles apart. 

Pests and Animals 

Burrowing pests that excavate soil will cause weak points in the compact soil under the patio. Animals that aren’t burrowers themselves may still seek out cavities beneath the slab as a den, and in doing so may cause further damage to the earth. 

The creation of burrows also creates a pocket of air just waiting to collect water during flooding. Even without water further softening the soil, a network of burrows can weaken the integrity of the soil, eventually leading to a sinking or cracked patio. 

You can read more about animals that can damage your home!