Back to help and advice menu

What are sinkholes and are they a danger to my home?

To put it simply, sinkholes are holes that open up in the ground. Sometimes sinkholes are small. And sometimes, they’re monstrous.

When we see monstrous holes opening up wide enough to swallow multiple semi-trailer trucks on the news, it’s shocking. The sinkhole seems to have come out of nowhere but the truth is they’ve been developing for a long time.

A few facts about natural sinkholes

In nature, sinkholes occur when water travels through dissolvable rock such as limestone or gypsum. As more water travels through the rock, it creates voids underground. Eventually, the void is so big, the ground above collapses, creating the sinkhole.

These kinds of sinkholes are really of no concern to people who live in urban areas. However, the principles behind the cause of sinkholes in urban areas are the same.

Uneven sinking of your home’s structure can lead to unevenness of the foundations directly beneath your interior and exterior walls. If your exterior or interior walls shift downward a little more than the other, the shifting can cause the ties within the walls to snap, tear and disconnect completely.

Urban areas

Under the surface of any urban area are thousands of pipes and drains. Some are for water, some are for sewerage and others are for stormwater.

When these pipes and drains aren’t taken care of, they can crack, leaking water into the surrounding soil. The soil that surrounds these pipes quickly becomes oversaturated causing soil erosion.

This oversaturation and soil erosion causes a variety of things to occur. Soil travels into the pipe and is carried away. And chemical reactions between water and soil can also cause aeration and weakness of the soil.

Over days, months and even years, voids form. If the voids become large enough the ground above eventually becomes so weak it collapses, creating a sinkhole.

Are sinkholes a danger to my home?

While the kinds of sinkholes that swallow trucks on the news are unlikely to appear in your neighbourhood, smaller sinkholes still can. On top of human error and poor workmanship, sinkholes occur because of plain old bad luck.

If you’re ever concerned about a sinkhole forming beneath your home look out for —