Spotting Subsidence

If your home has a history of subsidence, even if it has been fully repaired, you will probably have a great deal of difficulty obtaining future subsidence insurance. At HomeProtect we hear every case in full and deliver our quotes based on the risk to your property now, rather than assuming in every case that it is still suffering from subsidence.

If you have noticed cracking in your walls you might be feeling a little worried, particularly if you live in an area prone to subsidence issues, but don't panic just yet. Before you start phoning round for underpinning quotes, you need to be sure what's causing the cracking and that it is actually something structural, and that it is severe enough to warrant such drastic action.


Almost all buildings eventually develop cracks. Part of the natural lifespan of a house involves it expanding and contracting in accordance with temperature and moisture changes, as nearly every new build sinks into the ground a little as they settle. These factors are usually accounted for in the design and construction stages, so as to minimise the adverse effects on your home. The real trick is identifying when your crack is caused by something more structurally significant, such as subsidence or heave, and when it is a benign effect of seasonal change.


Cracks that are linear and less than three millimetres in width are very often found in new-build properties, and often result from the property 'settling' into its surroundings. When you have an extension added to your house, because they also need to settle, you are likely to find that cracks appear at the joint where they connect to the main building. This can also happen with bay windows over time. These types of cracks can be benign, or they can be the result of insufficient (or non-existent) footings or foundations for the size and weight of the new 'addition' to the property.

Seasonal effects

If you notice a crack becoming wider during a dry spell, this can be related to a form of subsidence, but again is not necessarily disastrous. Typically found in older properties, cracks expanding and contracting with the seasons need not be a sign that the property is suffering from structural damage such as subsidence. Many older properties either don't have foundations (as we would know them today) at all, or they simply have very shallow foundations. This seasonal cracking is very often the property 'breathing' in and out with the seasons of the year and, more precisely, the moisture content of the air and soil around it. However, if cracks open up very wide and/or refuse to close up again when rainy seasons return, that is when subsidence problems can be considered severe enough to warrant concern. In that event, if you have not already done so, you should call your insurer immediately so that investigations can be carried out into the cause of the cracking.


Other signs of structural movement might be observed by buckling wallpaper in the corners of rooms, as well as doors and windows sticking or becoming impossible to open/close. A subsidence related crack is usually characterised by being tapered, diagonal in nature, visible internally and externally on your property, and very often extends below the damp-course. If you experience these things and have reason to suspect subsidence, then you should contact your insurer as soon as possible.


Insurers will usually dispatch a surveyor to asses your property in the event of a suspected subsidence claim, who may in turn request the assistance of a structural engineer. At this stage, it may still turn out that there is little cause for concern. Depending on the cause of the structural movement, repairs could be as simple as filling in cracks and redecorating where necessary, though it is likely that markers will be used to monitor any possible future movement. If your case is severe enough to warrant extensive structural work being undertaken, it is quite likely that you will have to vacate the premises for a substantial period of time.

Please note: the content of these articles is for the purposes of information only and does not constitute advice. As soon as you spot, or become aware of, any cracking or other signs that your property may be suffering from structural damage, you should contact your insurer.

You must always act with due care and diligence in the ownership of your property. Avantia Insurance Limited accepts no liability or responsibility for the actions you take as the result of reading these articles.

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What can you do about subsidence?

Subsidence is the downward movement of a building’s foundations caused by changes to the surrounding ground soil. You must contact your insurer if you suspect subsidence. They will arrange for a professional survey to confirm the cause. They might also monitor how much the property moves over several months before starting repairs. Your home will likely need structural supports such as underpinning to strengthen the foundations.