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Table of Contents
- Causes of cracks in walls
- Should I worry about a crack?
- What causes wide cracks?
- Why are diagonal cracks a problem?
- What causes cracks above door frames?
- What causes cracks in new-build homes?
- Will my buildings insurance cover cracks?
- What is subsidence?
- Is subsidence covered by buildings insurance?
- Will subsidence show in a survey?
It can be alarming to see a crack in the wall or ceiling of your home. Most cracks are harmless, but others could be a sign that something more serious is wrong with your house.
You can repair and decorate minor cracks yourself, while more serious cracks might be covered on your home insurance.
Here’s more on the different types of cracks that can appear in your home, and what you should do about them.
Causes of cracks in walls
Cracks in walls are usually considered normal in different types of houses – including new-builds – and can indicate a natural settling of the structure. However, cracks can also be caused by fluctuations in temperature or humidity levels, as well as vibrations caused by nearby traffic.
Here’s a summary of the most common causes of cracks in the interior of your home.
- Settling when a new build home ‘settles’ into its foundations
- Wear and tear as your home and its foundations move gradually over time
- Newly plastered walls cracking after they dry
- Leaks due to escaped water somewhere in your home
- Vibrations from heavy traffic nearby
- More serious structural issues such as subsidence
Should I worry about a crack?
Small or hairline cracks are usually nothing to worry about. But there are some types of cracks you should get checked out. These include:
- Wider cracks of more than 5 millimetres
- Diagonal cracks
- Cracks above door frames
- Cracks through which you can see sunlight
What causes wide cracks?
The wider the crack is, the greater the cause for concern. Cracks of less than 5 millimetres wide are usually a crack in the plaster, rather than the wall itself, and can be filled and decorated over.
Cracks between 5mm and 15mm wide are more likely to be serious and may need professional repairs. Any crack bigger than 25mm wide should definitely be examined by a professional.
If the crack is wider at the top than the bottom, and visible on both the outside and inside of your home, you might have subsidence.
Why are diagonal cracks a problem?
Vertical cracks often occur when a wall is plastered – the plaster expands when it’s humid and then shrinks when it dries. These cracks are rarely anything to worry about.
Diagonal cracks or those that look like a staircase going up a wall are more serious. These cracks could be a sign of structural movement or damage and should be investigated by a structural engineer.
What causes cracks above door frames?
You should also get cracks around door frames checked out. These cracks could also be a sign of damage to your home’s foundations.
Wherever the crack is and however it presents, being able to see daylight through the crack could indicate a serious problem. It normally means the whole wall has shifted and, again, could be a sign of subsidence.
What causes cracks in new-build homes?
Many new-build homes develop cracks. These are usually caused by settlement, shrinkage or thermal movement, and are normally nothing to worry about.
According to the National House Building Council (NHBC), a home may experience some minor cracking as it ‘settles down’ on its new foundations. The ground underneath the home can compact under the weight of the structure, which causes the home to move downwards. Settlement usually occurs in newer properties, but it soon stabilises.
Shrinkage happens when materials such as mortar, plaster and concrete, which all contain water, shrink as they dry out. This may lead to minor cracks in walls and floors in the months after you move in.
Thermal movement is related to seasonal temperatures and weather changes. The different materials used to build your home respond differently to changes in temperature, moisture and humidity; these small movements can cause minor cracks to occur where the different materials meet one another.
Will my buildings insurance cover cracks?
Small, cosmetic cracks caused by a property settling or plaster drying won’t be covered by your home insurance. This is classed as ‘wear and tear’ and you’ll have to pay repair and decorating costs yourself.
If the cracks are caused by an escape of water, such as a leaky drains, you might be able to claim under the ‘escape of water’ clause of your insurance policy.
If the cracks are caused by subsidence, you can usually claim on your buildings insurance policy.
What is subsidence?
Subsidence is when the ground underneath your house sinks. This will impact the foundations of your house. If the ground under your property sinks at different rates. the foundations of your home can become unbalanced. This will move the walls and floors of your house from their original positions and lead to cracks in walls and ceilings.
Cracks caused by subsidence are usually diagonal, more than 3mm wide, near doors and windows, and can be seen from both the inside and outside. If you have subsidence, you might also find that doors and windows start sticking, and your floors begin to slope.
Subsidence can be caused by tree roots too close to the property, clay soil, drought, nearby mines, or leaking drains.
Is subsidence covered by buildings insurance?
According to the Association of British Insurers (ABI), buildings insurance will usually cover damage to the structure of your property caused by subsidence.
Your insurer will send a specialist or structural engineer to your home to examine the damage and determine its cause. If the movement of your home can be easily stopped, repairs will usually be carried out straight away.
In the case of more severe damage, engineers may monitor the movement of your home over a period of time in order to work out a long-term solution. One option is to ‘underpin’ your property – this means strengthening or deepening the foundations to prevent further subsidence.
If you make a claim for subsidence on your buildings insurance policy, you’ll usually have to pay an excess of about £1,000. You are also likely to see your premiums rise in the future and may find it more difficult to get home insurance.
Will subsidence show in a survey?
Most people get a survey done when they buy a house. Either a HomeBuyer Report or a Building Survey will highlight if the surveyor suspects a property has subsidence. If subsidence is suspected, the surveyor will normally recommend you get a more detailed inspection done by a structural engineer and then follow their advice.
If you’re buying a property that has had subsidence in the past and been repaired, your conveyancer should ask the vendor for documents and guarantees relating to the work done.
