Subsidence results from the shrinkage or downward movement of the ground around the foundations of a building. As the ground moves, the foundations are in peril of failing and the building they support is at risk of potentially very serious damage.
On a brighter note, however, subsidence typically occurs over a fairly long period of time, before truly serious structural damage is caused. Therefore, the sooner the signs of any subsidence are spotted, the sooner remedial work may be undertaken and more serious damage averted.
As you might notice, however, these early signs are largely quite innocuous and might often be symptoms of nothing so serious as subsidence. So, just how may you spot subsidence and what steps might you take if you have any worries?
What are you looking for?
- Cracks in the walls – either on the inside, the outside or both of your house
- New cracks that appear unexpectedly and are more than about 3 mm wide in either the interior plasterwork of the brickwork outside that run vertically or diagonally and are tapered so that they are wider at the top than the bottom
- Cracks around naturally weaker points in the construction, such as door and window frames and cause them to jam
- Cracks in the exterior brickwork that tapers down to the ground, running through the damp proof course towards the foundations
- If you have an extension on your home, look out for cracks where the wall of the extension meets the main body of the house. These can mean the extension is pulling away from the original structure
- Rippling or rucking of the wallpaper caused by cracks appearing in the plasterwork beneath it
But any of this type of cracking is in any case quite normal and evidence of a harmless settling of the ground, as a new house, in particular, beds down into its foundations. Settlement like this is quite different to subsidence – a distinction made both by surveyors and insurance companies.
The Call to Action
If any of these signs give cause for worry about subsidence, the first step is to contact your home insurer, to discuss any provision for subsidence insurance covered by your policy.
In appropriate cases, the insurer is likely to ask for a surveyor’s report, assessing the likely causes of the problems you have spotted and whether subsidence may be the root cause.
These investigations are likely to be quite complicated and may take careful monitoring over a period of some time – at least 12 months, for example, to determine the rate at which any cracks continue to widen. This is another reason, of course, why the sooner you raise the alert about any worries about subsidence, the better.
How funding cuts can also contribute to subsidence
Government funding is the main source of funding for local authorities. Cuts to this funding, for example; council budgets in 2018, can bring financial austerity to practically every area of expenditure, including landscaping and tree maintenance.
Through the need to cut back on tree pruning and arboreal management, councils have unwittingly contributed to the damage caused by the untrammelled growth of tree roots, their absorption of huge volumes of water from the ground, the ensuing shrinkage of the soil, and the subsidence problems which follow as building foundations fail and collapse.
Trees that are left to grow out of control tend to spread their damaging roots still further during periods of hot, dry weather and the summer of 2018 was one of the hottest on record, explained an article in the Financial Times. As the ground shrinks, foundations near any neighbouring trees may cause parts of the building to rotate, with cracks spreading along its walls. The problem is especially severe in the south-east of the country, where some types of soil are capable of shrinking by as much as 10 to 15%.
In either case, however, any homeowner making a claim must expect a lengthy wait as the possibility of subsidence is investigated and the foundations dug out and exposed.