20-metre sinkhole opens up in St Albans

20-metre sinkhole opens up in St Albans

You’ll no doubt have seen in the news, the striking aerial photos and videos of the large sinkhole that opened up in St Albans on 1 October. The gaping hole measures 20m x 20m and 10m deep – that’s about the same length as two houses!

Thankfully, no one was harmed and no properties damaged, but the shocked residents of the street were quickly evacuated and are unlikely to be able to return to their homes for some time. More than 50 local homes also lost electricity and gas supply whilst it was isolated for inspection.

What is a sinkhole?

In basic terms, a natural sinkhole is a hole in the ground which opens up when the rock underneath is dissolved by groundwater.

Sinkholes most commonly form in areas where the underlying rock is soft chalk or limestone as these dissolve more easily with rainwater and underground streams.

They can vary greatly in size from a few metres to scarily large and form both gradually or suddenly – one of the world’s biggest sinkholes measures 662-metres deep and is in China.

Whilst sinkholes are most common in the US state of Florida, they are thankfully rare in the UK. Areas known to have large expanses of limestone in Britain are the Mendip Hills, the north of the South Wales coalfield, the Peak District, the Yorkshire Dales, the northern Pennines and the edges of the Lake District. Sinkholes, whilst rare, have also historically appeared in the underlying chalk beds of South-East England.

St Albans sinkhole

How we’re helping affected customers

Our claim’s managers Glenn Stevens and Luke Norman were quickly at the scene to provide help and advice to our customers impacted by the St Albans sinkhole. At this time, we don’t know the exact cause of the sinkhole, and although their homes are still habitable, making sure our customers are safe and able carry on with their lives as normal is our number one priority. This is why we’re providing alternative accommodation until the sinkhole and surrounding area is made secure.

Looking after your home

Sinkholes are unpredictable and can appear without warning so there’s little you can do to help prepare your home in advance, other than ensure you have adequate home insurance covering both your building and contents.

Sinkholes are rare in the UK – but warning signs that the land is fragile could include:

  • Damage around the foundation of a building e.g. walls, floors, and pavement
  • Doors and Windows may not shut properly
  • Slumping, sagging or slanting fence posts or trees
  • Plants dying unexpectedly where the underlying streams that feed them may be draining into a sinkhole
  • Formation of new ponds or small collections of water

If you have any concerns that your home may be in an area of risk, we advise speaking to your local council or insurance company for advice.

How to check for other home problems

Use our interactive checklist to help identify common signs of maintenance trouble in your own home or when viewing a property for sale. Select each area of the house to read the tips that can help you identify a potential problem and see the average cost to fix them.

Contact us

Get in contact with the right person to answer your queries, or just talk to us about how we can help you and your family.


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