Can you sell a house with subsidence?

What subsidence is, and why Kent sees a lot of it

Subsidence is the ground under a house moving downwards and taking part of the building with it. Because it rarely affects the whole house evenly, one part drops more than another, and that uneven movement is what cracks walls.

The most common cause is clay soil. Clay shrinks as it dries out in hot, dry weather and swells again when it gets wet. Trees and large shrubs make this worse, because their roots draw water out of the ground, sometimes some distance from the tree itself. Leaking drains cause subsidence the other way, by softening or washing away the soil under the foundations. Old mine workings and filled-in pits are a less common cause.

The British Geological Survey names Kent among the parts of Britain most susceptible to clay shrinking and swelling, because so much of the south-east sits on clay. That doesn't mean every Kent house has a problem. It does mean buyers, surveyors and lenders here are used to asking about it.

Subsidence, settlement and heave

Not every crack is subsidence, and the word gets used loosely. It is worth knowing the difference before you describe your house to anyone.

Settlement is a building bedding down under its own weight. It is normal in newer houses and extensions, usually happens in the first few years, and then stops. Hairline cracks in fresh plaster are often nothing more than this, or the plaster drying out.

Heave is the opposite of subsidence: the ground swelling and pushing a building upwards. It often follows a large tree being removed from clay soil, as the ground takes water back up.

The cracks that suggest subsidence are usually diagonal, wider at the top than the bottom, and thicker than a 10p coin. They tend to appear near doors and windows, which may also start to stick. Gaps opening where an extension or bay meets the main house are another sign. If you see these, a structural engineer can tell you what is going on.

How subsidence is investigated and repaired

If you make an insurance claim, the insurer will usually send a loss adjuster and often a structural engineer. They look for the cause: nearby trees, the soil type, the condition of the drains. Drains are commonly checked with a camera.

Monitoring is common. Engineers measure the cracks, and sometimes the level of the building, over several months so they can see whether the movement is continuing and whether it follows the seasons. This is the part that takes time, and it's why a claim can run for a year or more.

Most subsidence is dealt with by removing the cause, such as reducing or removing a tree or repairing a leaking drain, and then repairing the cracks once the house has stabilised. Underpinning, where the foundations are strengthened or deepened, is the exception rather than the rule. It is expensive and disruptive, and usually kept for cases where the movement continues after the cause has been dealt with.

At the end of a claim you should get a certificate of structural adequacy or a similar letter from the engineer confirming the repair. Keep it. It's the single most useful document when you come to sell.

What you have to tell a buyer

In England, sellers fill in the Law Society's property information form, known as the TA6. It asks about subsidence, underpinning and other structural repairs, and separately about any buildings insurance claims, including ones for subsidence.

Answer it truthfully and completely. If you give a buyer wrong or incomplete information, on the form or in conversation, they can claim compensation from you or refuse to complete. That applies whether the information goes through your solicitor, your agent or directly to the buyer.

You aren't expected to know things only a survey would find, or what happened before you owned the house. You are expected to say what you know. Past subsidence that was properly repaired, with paperwork, is far less damaging to a sale than anything a buyer's surveyor finds that you didn't mention.

How it affects mortgages, insurance and price

Most buyers need a mortgage, and the lender decides whether the house is acceptable security. Lenders will usually want evidence that any movement has stopped and been dealt with: an engineer's report, the repair certificate and, where there was a claim, the insurer's paperwork. Some lenders won't lend on a house with active or unresolved movement at all.

Insurance matters just as much, because a lender won't release money on a house that can't be insured. A subsidence history usually means higher premiums and a larger subsidence excess, and some insurers will decline. If you're selling, ask your current insurer whether they would offer cover to a buyer on the same terms. A buyer who can pick up existing cover has one less reason to walk away.

If you have a claim still open, ask your insurer how it would be handled if you sell before it's finished, and whether it can be transferred to the buyer. Selling part way through a claim is possible but needs care, because the buyer will want to know exactly who is paying to finish the repair.

On price, there is no fixed discount. Historic subsidence that was repaired years ago, with a certificate and no further movement, may make little difference. Active movement with no investigation and no claim is a different house to sell, and buyers will price in the uncertainty and the cost of finding out.

Your options for selling

Fix it first, then sell on the open market. This usually gets the highest price, as long as the repair is signed off and the house can be insured. It is also the slowest route. Investigation, monitoring and repair can take a year or more, and you carry the house, and its bills, all that time.

Sell on the open market as it is. Possible, especially with good paperwork, but expect fewer buyers, a longer sale and a higher chance of a buyer's lender pulling out after the valuation or survey. A sale that falls through late costs you time you can't get back.

Sell at auction. Auctions attract buyers who expect problems, including cash buyers who don't need a lender's approval. A traditional auction sale is binding when the hammer falls, and usually completes within weeks. There are fees on both sides, and the price depends on who turns up on the day.

Sell directly to a buyer who buys in any condition. You get one figure for the house as it is, with no chain and no buyer's lender to satisfy. It is usually lower than a repaired house would fetch on the open market, because the buyer takes on the problem, the cost of fixing it and the time it takes.

The right choice depends on what the problem is, how much time you have and what the house is worth once repaired. For some people, a year of monitoring and building work is fine. For others, an empty house, a probate deadline or a move elsewhere makes it impractical.

Before you decide

• Find every document you have: surveys, engineer's reports, repair certificates, drain surveys and insurance correspondence
• Ask your insurer where any claim stands, and whether cover could pass to a buyer
• If there has never been an investigation, consider getting a structural engineer's view before you market the house
• Get the house valued as it is today, and ask what it would be worth once repaired
• Compare the two after taking off the cost of the repair and the months it would take