Everything You Need To Know About Sinkholes

Many homeowners worry about the possibilities of sinkholes in their driveways. But it shouldn’t be given too much thought as the likelihood that one would appear in your drive is pretty low, despite what you might see in the news. To put your mind at rest we’re here to tell you everything you need to know about sinkholes.

What Is a Sinkhole?

Basically a sinkhole is any hole in the ground that is created by erosion and water drainage. They vary in size and can be just a few feet across and pretty harmless or wide and deep enough to swallow entire buildings and cars.

What Are The Different Types?

There are two different types of sinkholes. A cover-subsidence sinkhole is one that is created slowly over time . A cover-collapse sinkhole is one that appears suddenly. Usually there are signs and symptoms of the former that can indicate what is happening and certain measures can be taken to avoid any harm or injury to properties and people. The latter is the type of sinkhole that usually makes it onto the news as they appear out of nowhere and take people by surprise. However, both types of sinkholes are formed in the same way.

Why Do Sinkholes Occur?

Sinkholes are most common in areas with karst terrain. Karst terrain is defined as areas of land where limestone, salt beds, gypsum and other carbonate rocks can be dissolved by water. When excess water penetrates the rock, either through extreme flooding, broken water pipes or some other source, it begins to eat away at the rock until a pit is formed. Over time, the sediment layer which is above this rock can no longer support itself and it collapses into the pit - causing the visible sinkhole. With cover-subsidence sinkholes this process occurs gradually over time, the bedrock slowly becoming exposed, but with a cover-collapse sinkhole the process occurs out of sight which makes it really hard to detect. Sinkholes are almost always a combination of natural forces and human activity.

How Can They Be Fixed?

Most sinkholes can be fixed by filling them in with sand, concrete and cement. For really large holes that are a danger to the public emergency personnel will need to be contacted and the proper measures taken to rectify the problem.

How Common Are Sinkholes In The UK?

Whilst we do get sinkholes in the UK, they are usually quite small and/or in rural, upland locations. The areas most prone to sinkholes are where there a lot of underlain limestone such as in the Peak District, Yorkshire Dales and parts of Wales. Parts of Dorset, Hampshire and the Chilterns where there are areas covered by younger clay and sand deposits are also prone. As are places where there are gypsum deposits, most notable in the north-east of England, specifically in Ripon. Here at Premier Surfacing, when we create our driveways in Staffordshire, Shropshire and Cheshire we always ensure any excavation work doesn’t disrupt water pipes or cause any other structural damage.