Subsidence: How to spot it and what to do
Subsidence is when the soil underneath a building gradually erodes and causes the structure to sink into the ground. Subsidence can happen to any building, though some are more susceptible than others.
It is very important to spot subsidence early on as the costs of repairing deep structural damage to a building can be huge. There are typical signs of subsidence that you should keep an eye out for, and there are also preventative measures you can take to help ensure your property is free from subsidence.
So what are the signs of subsidence? How can you prevent it? And what fixes are available for a building that has already succumbed to subsidence?
We will take a look at subsidence, what it is, how to spot it, how to fix it, and what insurance you need to protect yourself against it.
What is subsidence?
Subsidence is when the ground beneath a building sinks and pulls the foundations and the building down with it. Tell-tale signs of subsidence include cracks in the walls, rippling wallpaper, and windows and doors that no longer fit their frames.
Subsidence is repairable, and you should try to get it fixed as soon as you notice it, as leaving it for too long can result in serious structural issues that are much harder to repair.
So let’s jump in and take a closer look at some of the classic signs of subsidence.
How to spot subsidence
Unless a building has been swallowed into the ground, you usually can’t actually see subsidence. However, you can see evidence of subsidence by inspecting the building and recognising some signs that should alert you to the problem.
Cracks in the walls
Cracks in the walls are the most common sign of subsidence. Some cracks are harmless and just a natural part of the ageing process of the building. So how do you tell the difference?
Cracks caused by subsidence usually have a few signs that should make it obvious:
The crack is wider at the top than it is at the bottom.The crack is wider than half an inch.The crack can be seen from both inside and outside the building.The crack is positioned nearby windows, doors, or structural pillars.
In all of these instances, the crack in the wall is likely indicative of subsidence, and you should enlist professional help to fix it.
Rippling wallpaper
As with wall cracks, rippling wallpaper can be caused by many things unrelated to subsidence, namely condensation and dampness.
One way to check whether the ripples in the wallpaper are caused by dampness and condensation is to inspect the windows in the room of the rippling wallpaper either when it is cold or in the mornings.
If your windows show signs of condensation, then it is likely that the room has an issue with dampness and may need a dehumidifier. If the windows show no signs of condensation, then the rippling wallpaper could be due to subsidence.
Doors and windows that don’t fit the frames
If you notice that the doors and windows in parts of your house no longer properly fit their frames or are perhaps tighter to open than they once were, it may well be a sign of subsidence.
What causes subsidence?
Subsidence can happen anywhere, though it is more likely to happen in certain places due to the clay and solid underneath the building, the trees in the surrounding area, any mines located nearby, and the quality of the foundations laid beneath the building.
Let’s take a look at some of the most common causes of subsidence.
Shrinking clay
When the weather is warm, the water within the ground evaporates, which causes the clay in the soil to shrink. As the clay shrinks, the ground above it is pulled down due to the tightening of the surface. This can cause subsidence in properties built on top of the shrinking clay.
Nearby trees
Similar to warm weather, trees can also dehydrate clay within the surrounding soil and cause it to shrink. This is because trees draw water from the earth around them, sometimes as much as 1,000 litres of water a day!
Tree roots can also create issues within the foundations of a building. This can cause the ground to become less stable and lead to further subsidence.
Soil dispersion
Soil dispersion can be considered the opposite of shrinking clay, though both can lead to subsidence.
Soil dispersion is caused by wet weather, flooding, and leaking pipes or drains. Excess water washes away the soil, and the moisture slowly erodes the ground underneath the house. This causes the ground to shift or simply be less stable, resulting in subsidence.
Old foundations
Pre-war properties can have shallow foundations compared with newer builds, and the materials used to lay the foundations are older and more worn. This can lead to subsidence as the foundations are more likely to sink and cave over time.
How do you prevent subsidence?
You can do several things to ensure you minimise the chances of subsidence with your property. Here, we will take a look at some of the most effective methods.
Keep an eye on trees nearby your house
As we have seen, trees are a common cause of subsidence. So you should avoid planting any big trees in your garden or near your property unless the distance between the plant and the property is greater than the expected of the fully grown tree.
If there are trees in your garden or near your property already, then be sure to regularly prune the branches to prevent the roots from growing far enough and deep enough to cause damage. You should talk to a tree surgeon to help you develop a good strategy for doing this.
Check your guttering and plumbing
Leaking pipes and drains are a common cause of subsidence. So it is always a good idea to check the condition of your gutters and plumbing. Any water escaping can make the ground saturated and result in soil dispersion and subsidence.
Check your gutters and plumbing once or twice a year and if you think there may be a leak or another problem, then contact a professional to get it properly fixed.
How do you fix subsidence?
If you have noticed that your property already has subsidence, then fear not, as there are a number of fixes that should help with the problem.
However, before you approach any of the fixes, you should first contact your insurer and ask for their advice on the first steps you should take.
Your insurer is likely to recommend one or more of the following options.
Underpinning
Underpinning is an expensive remedy for subsidence and is usually only used in extreme cases and after all other options have been exhausted.
Underpinning involves digging out the ground and soil beneath your house and replacing it with materials that are more durable and less likely to subside.
Underpinning does not guarantee to fix the subsidence altogether, and if you have reached the point at which it is recommended as a solution, then the property may already be too far gone.
Tree removal or management
If a tree causes subsidence, then a tree surgeon should be able to advise you on the best way to deal with it. It usually involves chopping the tree entirely or pruning its branches to limit its growth.
Plumbing repairs
Leaking drains and pipes are a common cause of subsidence. If you think that is the cause of the subsidence of your property, then a plumber should be able to fix it for you.
What happens if you ignore subsidence?
Ignoring subsidence or the signs of it is the worst thing you can do. Subsidence usually happens very slowly over a number of years, so people often either don’t realise it is happening or they defer dealing with it to a later date.
Keep an eye on the tell-tale signs of subsidence outlined above, and be sure to act as quickly as possible if you think subsidence is becoming an issue for your property.
Failure to do so can lead to:
Serious structural issues. In the worst cases, the cost of repairing the damage could be more than the value of rebuilding the property.A reduction in the value of the property. Serious subsidence costs a lot to fix, so anyone looking to buy a property with such issues will want a lower price than other similar properties would cost.Higher insurance premiums. Insurers understand the cost of subsidence better than anyone, so if you fail to act early, then your home insurance bills will undoubtedly rise to cover impending costs.
Does home insurance cover subsidence?
You can get specific subsidence insurance, but most buildings insurance policies should cover subsidence, and you should try and get it included on your policy if it isn’t already.
Home insurance is split into two categories: buildings insurance and contents insurance. Buildings insurance covers the structure of your property, and contents insurance covers the items within it.
Although neither is technically required by law, mortgage lenders almost always stipulate buildings insurance as a prerequisite to the mortgage. So without buildings insurance, you usually cannot get a mortgage.
Even if you own your property outright, don’t have a mortgage, and are not required by a mortgage lender to have a buildings insurance policy, you should get one anyway. The costs of repairing the structure of a building can be huge, and, as we have seen, issues such as subsidence can creep up slowly over time before you realise there is a problem.
Summary
Subsidence occurs slowly over a long period of time and so is often not noticed until it starts to cause serious issues to the building. You should keep your eye out for some of the key signs of subsidence, such as cracked walls, rippling wallpaper, and doors or windows that no longer fit their frames.
However, sometimes it is too late, and the subsidence has already set in, and you will need to pay for a fix to ensure it doesn’t get any worse. In the case of such an event, you will need subsidence insurance or buildings insurance at the very least. A-Plan’s subsidence insurance is tailored to your needs and ensures that your property has the exact level of cover required.
