Subsidence

It is a sight to instil fear in any homeowner's heart - the appearance of cracks in the walls of your home. However, whilst they may look alarming, the development of cracks does not necessarily mean that you have a major subsidence problem. Most buildings experience cracking at some time and so there is no need to be alarmed by every crack that appears.

What is Subsidence?

Subsidence is the downward movement of the ground that supports the property. Problems particularly develop when the movement varies from one part of the building to another.

It can be caused by:

• Vegetation: Trees and shrubs take moisture from soils. This causes the soil to shrink, particularly during long periods of dry weather, when roots extend in search of water.
• Particular soils: Clay soils are especially susceptible to subsidence, as they swell and shrink depending on their moisture content.
• Damaged drains: Leaking drains can soften or wash away the ground underneath the foundations.

There are other types of ground movement that can result in cracking and structural damage, such as:

• Landslip: The movement of ground down a slope.
• Heave: The upward movement of the ground supporting the property.

Signs of Subsidence

The first obvious sign of subsidence is the development of cracks. However, not all cracks indicate that there is a problem.

For example, you shouldn't worry if cracks develop under any of the following conditions:

• Cracks are common in newly built extensions and properties. This is as a result of the building settling under its own weight.
• Newly plastered walls often develop fine cracks as they dry out.
• Minor cracks may appear where walls and ceilings meet. This is due to the natural shrinking and swelling of buildings, due to changes in temperature and humidity.

However, if small (usually diagonal) cracks suddenly appear inside in plaster work, or outside in bricks, there may be a problem. These cracks usually appear at weak points, such as around doors and windows, especially after long periods of dry weather. They will normally be thicker than a 10p coin, and usually be wider at the top. Doors and windows may also 'stick' due to the distortion of the building. This may, but not necessarily, indicate movement in the building's foundations.

If you have noticed any of these signs, contact your buildings insurer as soon as you possible so that they can give you help and guidance.

Minimising the Risk

Taking a few simple precautions can help reduce the risk of structural damage.

One of the most common causes for subsidence is having trees and shrubs planted too close to a property, and careful attention should be paid to the type, size and distance of any trees and shrubs from your home.

You should also consider the proximity of trees to underground drains and buildings - including any belonging to neighbours.

Make sure that trees and shrubs are pruned regularly. You should also carry out regular general maintenance checks around a property, to make sure that there are no blocked or leaking drains and that dirt and leaves are cleared from gutters.