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How Can I Tell if My House is Subsiding?

Tuesday, August 29, 2017 - Sponsored by

Uretek

When a building subsides, or sinks there can be several reasons.

Knowing the precise nature of the cause and what impact it has is important to know, especially when it comes to buildings insurance and property valuations.

Crack damage to buildings can be the result of many causes, occurring either independently or together and it is not automatic that subsidence of the site is one of them; indeed, on most occasions the cracking will be due to other causes.

A chartered surveyor will be able to work out whether there is subsidence and what the likely cause is.  It is imperative that whoever is engaged to inspect the damage has adequate training and experience to be able to ascertain whether the damage is consistent with foundation movement or some other cause.

You may also need specialist geological and drain surveys. Moving soil can sometimes crack drains or water mains.

What is subsidence and how is it caused?

The area of the damage to the superstructure is not necessarily the same location as any movement in the foundations.

The location and nature of the damage should enable the source of the movement to be determined. Subsidence usually happens where:

  • some houses are built on clay soil, and either the water table drops due to a long, dry spell or water is sucked out of the soil
  • by trees and bushes. As the clay shrinks it pulls the foundations, triggering deflection which may cause structural damage to buildings. Different types of clay shrink and swell at different rates
  • water leaks into the soil from, for example, a broken drainpipe and washes soil away from the foundations. This happens to soil with a high sand or gravel content usually, or sometimes in chalk
  • previous mining activity has taken place.

How can I tell if my house is subsiding?

A subsidence problem affects the foundations and has the potential to impact the stability of the building - you’ll see diagonal wall cracks. For a subsiding property, the problem is the ground itself; something will have happened to the composition of soils meaning it will become weaker, or the original foundations were not sufficient for the ground in the first place.

There could be movement in the ground beneath your home if you find:

  • new or expanding cracks in plasterwork
  • new or expanding cracks in outside brickwork
  • doors or windows sticking for no reason
  • ripping wallpaper that isn’t caused by damp.

If you spot any of these problems and can’t find a reason for them, get specialist help as soon as possible.

If it is subsidence, the sooner it is diagnosed the better. It’s important to remember that subsidence can usually be rectified. Check that your buildings insurance covers subsidence. Most insurers will aim to be as helpful as possible in dealing with any claim. They will recommend specialist advice.

A subsidence problem affects the foundations and has the potential to impact the stability of the building - you’ll see diagonal wall cracks. For a subsiding property, the problem is the ground itself; something will have happened to the composition of soils meaning it will become weaker, or the original foundations were not sufficient for the ground in the first place.

An RICS member will be able to work out whether there is subsidence and what the likely cause is. You may also need specialist geological and drain surveys. Moving soil can sometimes crack drains or water mains.

Image: s2ar

 

Uretek