Question 1

What is subsidence?

Accepted Answer

Subsidence is the downward movement of the ground beneath a building's foundations, which causes the structure to sink or shift unevenly. It's different from settlement, which is the normal, even bedding-in of a new building. Subsidence often shows up as cracks in walls, sticking doors and windows, or sloping floors, and usually needs professional investigation to confirm the cause.

Question 2

What are the signs of subsidence?

Accepted Answer

The most common signs are new or widening cracks in walls (especially diagonal cracks wider than 3mm, often near windows and doors), doors and windows that suddenly stick, rippling wallpaper, and sloping or uneven floors. Cracks caused by subsidence are typically wider at the top than the bottom and visible inside and outside. If you notice these, it's worth getting a professional assessment rather than worrying — many cracks turn out to be harmless.

Question 3

What causes subsidence?

Accepted Answer

The most common causes are clay soils shrinking in dry weather (the leading cause in the UK), tree and shrub roots drawing moisture from the ground, leaking or damaged drains washing away soil, and previous mining or made-up ground. Older properties with shallow foundations are more vulnerable. A proper investigation identifies which of these is the actual cause, since the right repair depends entirely on getting that diagnosis correct.

Question 4

Is subsidence covered by home insurance?

Accepted Answer

Subsidence is covered as standard under most UK buildings insurance policies, usually subject to an excess (commonly around £1,000). If you suspect subsidence, it's important to contact your insurer and arrange a professional investigation. An independent expert report clearly setting out the cause and recommended action is often essential for a smooth insurance claim.

Question 5

How is subsidence diagnosed?

Accepted Answer

Diagnosis usually starts with a visual structural assessment of the cracking and damage, followed by investigation of the likely cause — this can include soil sampling, trial pits to inspect the foundations, drainage surveys (CCTV), and a check of nearby trees. In some cases, crack monitoring over a period of months confirms whether movement is ongoing. The result is a clear report identifying the cause and the appropriate remedy.

Question 6

How much does a subsidence investigation cost?

Accepted Answer

Costs vary depending on the size of the property and the level of investigation needed. A basic structural assessment is relatively modest, while a full investigation involving soil testing, trial pits, and drainage surveys costs more. Where subsidence is covered by insurance, the investigation is often handled as part of the claim. We provide a clear quote up front so there are no surprises.

Question 7

Can subsidence be fixed?

Accepted Answer

Yes. Most subsidence cases are resolved without underpinning. If the cause is a leaking drain or a thirsty tree, simply fixing the drain or managing the vegetation often allows the ground to stabilise. Underpinning — strengthening the foundations — is reserved for more serious cases. The key is correctly identifying the cause first, which is exactly what a proper investigation provides.

Question 8

How long does subsidence monitoring take?

Accepted Answer

Where the cause isn't immediately clear, monitoring typically runs over a period of several months (often through different seasons) to confirm whether the building is still moving and what's driving it. This patience pays off, because it avoids unnecessary and costly repairs by pinpointing the true cause before any work begins.

Question 9

Will subsidence affect my property's value or sale?

Accepted Answer

A history of subsidence must be disclosed when selling, but a property that has been properly investigated, treated, and certified as stable is very different from one with an unresolved problem. A clear, professional report showing the cause was identified and resolved gives buyers and their lenders confidence, and is the best way to protect your property's value.

Question 10

What should I do if I think my home has subsidence?

Accepted Answer

Don't panic — many cracks are cosmetic. Note when you first spotted the cracks and whether they're growing, take photographs, and avoid any major repairs until the cause is known. Then contact your insurer and arrange a professional investigation. Getting an accurate diagnosis early is the cheapest and least stressful path to resolving it.

Your subsidence questions, answered.

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