Spotting the signs of subsidence

Subsidence is a word that strikes fear into the hearts of property owners. And we are reliably informed by subsidence specialist Sedwick that weather conditions in 2020 could point to increasing levels of subsidence in properties around the country.

Subsidence is caused when there is a downward movement resulting from a change in ground conditions around and below a building. This can cause serious structural problems including cracks in walls and brickwork and can even make the whole property unstable. The majority of subsidence problems are in homes built on clay soils which are prone to expansion and contraction if heavy rainfall is then followed by dry weather. Properties built on the soil then start to move and shift, leading to cracks in walls and foundations. Trees can also cause problems as root systems may also affect subsoil beneath foundations. And leaking drains and pipes may have the same impact. So it is important to be aware of the signs that subsidence may be affecting your block.

Insurer AXA points out that if a crack is caused by subsidence, it will be:

• Thicker than a 10p coin (more than 3mm)
• Diagonal, and wider at the top than the bottom
• Visible internally and externally
• Found close to doors and windows

It may also extend below the damp-proof course (a layer of waterproof material in the wall of a building near the ground, used to prevent rising damp).

Other signs of subsidence include:

• Wallpaper crinkling at wall/ceiling joins
• Doors and windows sticking as frames warp
• Cracks where an extension joins the house

However, if you do spot a crack you’ve never noticed before, don’t panic, particularly if you’ve moved into a new-build flat. New or freshly plastered homes usually develop small cracks as plaster dries and the structure settles. And cracks are much more likely to be caused by natural shrinkage and swelling as temperature and humidity change.

Your property manager should be able to identify any potential structural problems but even property professionals can miss something, so if you spot a new crack in the external walls of your block – or in the walls or ceiling of your flat - let us know.