There is really no good news about subsidence. The only question is how bad the issue is and hence how much time and effort and money it’s going to need to put right. Having just said that, subsidence may not be as bad as you think, especially if you catch it early.
Speaking of which, if you’re in the market for a new property, it can be a smart move to have a surveyor check not just for existing subsidence, but for any evidence that subsidence might become an issue in the future.
The basics of subsidence
Subsidence is what happens when something causes the ground underneath your property to shift with the result that the foundations of the property become strained and the property on top of them becomes unstable.
If the instability is severe, it may lead to structural damage and, in a worst-case scenario may lead to the property collapsing completely, although it must be emphasized that this last situation is extremely rare.
Signs of existing subsidence
In and of themselves, cracks are not necessarily a sign of subsidence. If the property is fairly new, they are quite likely to be a sign that it’s had to “settle into” its foundations (most properties do) and this has caused a few cracks which have yet to be fixed.
If the property is older, it could be a sign that its foundations aren’t up to modern standards and/or that it could do with some general maintenance, both of which will need to be re-valued but neither of which is necessarily a huge cause for alarm.
The cracks which are a cause for alarm are broader ones (more than 3mm), which are visible both inside and outside the home. They are typically wider at the top than they are at the bottom and run on the diagonal (in either direction).
The places you are most likely to see these cracks are near doors and windows and also where extensions are joined to the main building.
Subsidence and property purchases
In principle, the seller should disclose any issues with the property, provided they know about them or should reasonably have known about them. It’s usually hard to deny knowing about any existing subsidence issues so, in principle; you should expect to be informed about them.
That said, as the saying goes “let the buyer beware” and having a surveyor undertake a thorough check of the property is usually vastly more affordable than repairing undetected subsidence and vastly less hassle than legal action against a seller.
A surveyor can also check for signs that the property may be vulnerable to subsidence in future and a seller may genuinely not know about these.
Even though subsidence is a serious issue, it doesn’t have to kill a property purchase; you just need to factor the risk into the price you’re willing to offer for the property.
While a lot of subsidence does come about as a result of the natural environment or historic human activity (such as mining), and some comes about due to issues beyond your control (for example local authority building works or heavy traffic), there is a lot you can do to protect your property from subsidence.
In particular take steps to ensure that nothing disturbs its foundations (like tree roots) and that water drains cleanly away from your property without pooling.