Does home insurance cover cracked render and walls?

Concerned cracks could be subsidence? The cause is usually less sinister

Kim Jones
Kim Jones
Updated 21 July 2023  | 3 min read
Reviewed by Jasmine Hembury

Information on this page was reviewed by our fact-checkers before it was published. Learn more about our fact checking process and our editorial guidelines.

What causes cracks in walls and render?

Although some cracks are warning signs that the ground beneath a building is shifting and causing structural damage, most are harmless.

Common causes of minor cracks include:


All new buildings – or new extensions to homes – settle downwards under their own weight. This can cause cracking without any threat to the structure.

Usually, settlement cracks appear at weak points, like around windows and doors.

It can take a couple of years for a building to settle, so you can expect some minor cracks to appear in new builds for quite some time.

Temperature and humidity

All buildings, new and old, expand in the heat and contract in falling temperatures. You may have even heard creaks or snapping sounds as these movements occur.

Thermal cracks caused by this sort of movement are minor and easily repaired.

In newly-built homes, moisture in building materials like wood, concrete and mortar dries out over several months. This results in some shrinkage, which can lead to cracks, usually near ceilings and floors.

In homes old and new, cracks can appear when building materials expand and shrink depending on how much moisture is in the air.

Materials expand as they absorb the water vapour that’s expelled in our homes when we take baths and showers, or boil kettles and cook, for example. Then they shrink as they dry out when it’s warm outside or when the central heating is on.

Cracks can also be caused by:

  • Water damage
  • Vibrations from heavy traffic or construction work
  • Ageing and wear and tear
  • Freshly plastered walls drying out or ‘blown’ plaster

Key points

  • Cracks appear on the walls of most homes. They’re normally nothing to worry about and won’t affect the stability of your property
  • Harmless, cosmetic cracks can be caused by anything from your home ‘settling’ to temperature changes
  • Subsidence and heave are the most serious causes of cracks appearing in your home
  • Cracks caused by these sorts of ground movements are typically much larger – more than 5mm wide -and often run diagonally

When should I worry about cracks in my wall?

Minor cracks that measure no more than 2mm are usually nothing to worry about and will have no effect on the safety and stability of your property. You can easily check the width of cracks with a measuring tape.

But you should investigate cracks that:

  • Measure more than 2mm wide along their full extent, especially those that run diagonally
  • Are more than 5mm wide at any point in the crack
  • Are wide at one end and narrow at the other
  • Can be seen on both inside and outside walls
  • Have become wider or longer over time

These sorts of cracks could be a sign of structural damage and subsidence.

When should I worry about cracks in my render?

Cracks and bulges in the exterior render of a property can happen for a variety of reasons, most of which aren’t serious. For example:

  • If the render dried out too quickly on application and didn’t attach to the wall properly, hairline cracks may appear
  • Because render is brittle it can crack due to thermal shrinkage and expansion
  • If the render is old, then it’ll have taken the brunt of years of rain, wind and heat and could crack or bulge as a result

Any crack in the render of your home should be attended to. Even small cracks can allow water to seep into the brickwork and cause more damage - like damp, or wider cracks if the water freezes in cold weather.

You can either cut out and fill these types of cracks or if the render is ‘blown’ and has become detached from the wall, it’ll need to be taken off and the render replaced.

Any cracks measuring more than 15mm should be investigated by a professional.

When are cracks in walls a sign of a problem with the structure itself?

Subsidence happens when the ground beneath a property erodes and moves downwards.

As the ground sinks, it pulls the property’s foundations down with it, damaging its structure and causing cracks.

Heave, on the other hand, is when the ground moves upwards, or swells, causing a property to lift. It’s less common than subsidence.

Heave and subsidence can occur when soil gets too wet due to flooding, or too dry due to excessive periods of drought.

These type of ground movements tend to happen in:

  • Areas that have peat or soft clay soil
  • In homes built where mining has taken place in the past
  • In properties with poor drainage or those that are surrounded by trees and shrubs that absorb excessive moisture from the soil

As well as wide cracks appearing, signs of subsidence can include:

  • Gaps appearing between the floors and walls
  • Sloping, uneven floors
  • Cracks in concrete floors and in garden paths
  • Doors and windows that become difficult to open and close tight
  • Cracks that appear on exterior brick walls that are zig-zagged and follow the lines of mortar

Types of wall cracks

The Building Research Establishment (BRE) identified six categories of crack to help surveyors and insurance assessors identify whether a crack is likely to affect a property and the type of repairs that would be appropriate.

Broadly speaking these are:

  • Hairline cracks where no action is required.
  • Fine cracks up to 1mm which can be treated with DIY and decoration.
  • Cracks up to 5mm in width, which can be easily filled. On the exterior of a property these may need to be repointed to be weathertight.
  • Cracks from 5mm to 15mm wide, which may need opening up and refilling by a professional. External brickwork may need repointing and some brick replacement.
  • Cracks 15mm to 25mm wide. These sorts of cracks can cause damage such as distorting window and door frames and some loss of bearing in beams. Work which may be required includes replacing parts of walls, especially over doors and windows.
  • Cracks more than 25mm can cause structural damage and stability issues. This is likely to require major structural intervention like shoring of walls, underpinning, partial or complete rebuilding.

Look out for the direction in which a crack runs through the wall as this can sometimes help determine how serious it might be and how to treat it.

  • Vertical cracks can simply be due to a house settling and are usually no cause for concern unless they grow larger with time.
  • Horizontal cracks can be indicative of foundation and structural problems and should be investigated by a professional.
  • Diagonal cracks that look like a flight of stairs on outside brick walls can be a sign of structural issues. Call in a structural engineer or surveyor.

How can I prevent cracks appearing?

In a newly-built home, you can help to keep cracks at bay by allowing building materials to dry out gradually so that shrinkage is not too sudden.

Try leaving window vents open to allow for natural evaporation of moisture and avoid cranking up the central heating too high as excessive heat can speed up the drying process and cause cracking.

If you live somewhere that’s prone to subsidence issues – such as a clay soil area – there are some things you can do to help prevent the problem.

  • Avoid planting large trees or shrubs that will dry out soil close to your home. If you already have a tree close to your property, get specialist advice before removing it, though. In some cases, if a well-established tree is removed, moisture in the ground will build up and could cause the ground to swell, resulting in heave, which can damage your property further.
  • Check that pipes, drains, gutters and plumbing aren’t leaking, as this can wash away soil.

How can I fix cracked walls?

When you next decorate, you can easily repair minor cracks using a filler, then lightly sanding before applying paint.

If a crack is wider and more severe, you should get the advice of a professional structural engineer. They can determine if they think the crack/s are an indication of structural damage and next steps to take.

What should I do if I'm worried about cracks in my walls?

If you suspect subsidence, you should contact your insurer.

They may send out a building specialist or surveyor to take a look.

The specialist might want to place monitors onto cracks to check for ongoing movement and to assess the ground below the foundations.

If movement of your home has stopped, then repairs to damage can go ahead.

If movement is ongoing and is causing major structural damage, then you may need to have your home underpinned. This involves lifting, re-levelling and strengthening the ground underneath the building.

Renters and leaseholders

If you’re renting, contact your landlord about any concerning cracks. And if you’re a leaseholder, contact the freeholder. It’s their responsibility to investigate the problem and to claim on their buildings insurance for repairs if necessary.

Does home insurance cover cracked walls?

Small, hairline cracks are normal as a newly-built property or extension settles, or as any home ages and is lived in.

Minor cracking is a cosmetic problem, and any repairs needed won’t be covered by buildings insurance.

Cracks that form as the result of subsidence, though, are usually covered by a home insurance policy.

This is true only if your home has not suffered subsidence in the past (though there are some specialist insurance policies that will cover properties with subsidence history.)

Your buildings insurance policy will cover the cost of repairing damage to the structure of your home that occurs as the result of subsidence, including cracks.

It won’t normally cover the cost of preventing further subsidence and movement of your home though.

Some policies offer to cover the cost of your accommodation if your home needs extensive repair and you have to move out.

Subsidence claims usually come with an excess in the region of £1,000.

Will claiming increase my premium?

Premiums and excesses usually increase after you’ve made a subsidence claim with your insurer, especially if it’s still at risk of further movement.

Some companies won’t insure you at all if your home has had subsidence issues as they see it as too much of a risk.

You may need to shop around for specialist insurers who will cover you.

Frequently asked questions

Most houses - old and new - have a few cracks in the walls. Cracks in old houses can often happen because of moisture and heat changes in the old brickwork and plaster over the years. Small, hairline cracks like this are nothing to worry about and can be repaired easily.

However, if you notice large cracks, diagonal cracks that are wider at the top than the bottom and that can be seen both inside and outside the house, it’s best to call in a professional structural engineer to diagnose the problem.

Buildings and building materials shrink and expand because of changes in temperature, humidity and moisture through the year. These changes can cause cracks and make existing cracks open and close. Thermal movement cracks like this are usually small and run vertically.

Any cracks that get significantly wider or longer over time could be cause for concern, so you should call in a professional. Monitor changes by measuring the width of the crack and marking the point where the crack ends with a pencil.

Small cracks that you’ve refilled may reappear a year or so down the line, most likely due to thermal movement. As long as the crack doesn't get markedly wider or longer, they’re usually nothing to worry about.

Compare home insurance quotes

Buy home insurance with us and we’ll refund up to £250 of your excess if you make a claim. Excludes accidental loss and damage claims^

Get quotes

^Up to £250 refunded after claim settled. Excludes accidental loss or damage claims. Full T&Cs apply.

See if you can save on your home insurance

Get quotes