Underpinning is the repair that follows subsidence. Engineers extend or strengthen the foundations so the building stops moving, and once it’s done properly the house is often more stable than its neighbours. That’s the engineering reality. The selling reality is different, because the word “underpinned” on a survey or a property information form makes buyers, lenders and insurers all pause. You can absolutely sell a house that’s been underpinned, and we buy them regularly, but the sale runs more smoothly when you understand what each of those three parties is worried about and what paperwork settles it. This guide covers the documents that matter, how underpinning affects a mortgage and insurance, your selling options, and what to expect on price.
Why Underpinning History Worries Buyers
The concern is rarely the underpinning itself. It’s three things sitting behind it.
- Will it move again? Buyers want to know the original cause of the subsidence was dealt with, whether that was tree roots, leaking drains or shrinkable clay, and that the building has been stable since.
- Can I insure it? Properties with a subsidence history are harder to insure on standard terms, and some insurers decline them outright.
- Will my lender accept it? Lenders generally lend on underpinned houses, but their surveyors look harder and may ask for documents the seller doesn’t have.
If you can answer all three with paperwork, most of the hesitation disappears. If you can’t, the buyer pool narrows considerably.
The Documents That Settle The Question
Gather these before you go to market. Each one addresses a specific worry.
The Structural Engineer’s Report
This should set out the cause of the movement, the investigation carried out, and the underpinning scheme designed to address it. If the work was done through an insurance claim, the insurer’s engineers will have produced this.
The Certificate Of Structural Adequacy
Issued by the engineer on completion of the work, this confirms the repairs were carried out to the design and that the building is structurally sound. Lenders and insurers ask for it by name. If you don’t have one, the engineer or the insurer who handled the claim may still be able to supply a copy.
Building Regulations Approval
Underpinning needs building control sign-off. The completion certificate from the council or an approved inspector shows the work was inspected.
Contractor’s Guarantee
Many underpinning contractors provide a guarantee, often ten to twenty years. Check whether it’s insurance-backed and whether it transfers to a new owner, because a guarantee from a contractor that’s since gone out of business is worth little unless it’s backed.
Insurance Claim History
If the work was funded by a claim, the claim file confirms the insurer accepted the subsidence and paid for a proper repair. Keep the correspondence and the settlement letter.
Evidence Of Stability Since
Monitoring reports from the period after the work, or simply a later survey confirming no further movement, carry weight. The longer the house has been stable, the less concern buyers have.
Mortgages And Insurance On An Underpinned House
Mortgages. Most mainstream lenders will lend on a house that’s been underpinned, provided the paperwork above is available and the lender’s surveyor sees no sign of ongoing movement. Some lenders won’t lend if the underpinning was within the last few years, and some require a structural engineer’s letter confirming stability regardless of how long ago it was done. A buyer applying to the wrong lender gets refused, which is where sales stall.
Insurance. This is the tighter constraint. Once a property has a subsidence claim, the existing insurer is usually obliged to keep offering cover, but a new owner can’t inherit that policy automatically. Specialist insurers will cover underpinned properties, often at a higher premium and with a larger subsidence excess. Some mainstream insurers will quote if the work is old enough and the paperwork is complete. A buyer who can’t arrange buildings insurance can’t get a mortgage, so it’s worth finding out what cover is available before you market the house and sharing that with buyers.
Your Options For Selling
The Open Market
If you have the full document set and the underpinning was more than ten years ago with no further movement, the open market works reasonably well. Price realistically, give buyers the paperwork early, and instruct an agent who’s sold underpinned homes before. Expect a longer sale than average and some buyers dropping out at the insurance stage.
Auction
Auction attracts buyers who expect structural history and price for it. You’ll get a binding sale on the day, with the paperwork in the legal pack for bidders to assess. Fees apply and the price depends on the room.
A Cash Buyer
If the paperwork is incomplete, the underpinning is recent, or you’d prefer a sale that doesn’t depend on a lender’s surveyor and an insurer’s underwriter both saying yes, a cash sale is the simplest route. We’ll buy a previously underpinned house for cash whatever the state of the records. We’ll ask for whatever documents you have, carry out our own survey at our cost, and make an offer within 24 hours of your enquiry. Legal fees and the EPC are covered, our offers fall between 70% and 85% of market value, and we buy across England and Wales.
What Underpinning Does To The Price
An underpinned house with a complete file, a stable history and available insurance sells at a small discount to an equivalent unaffected property, sometimes very small in areas where subsidence is common and buyers are used to it. The discount grows when documents are missing, when the work is recent, when the cause isn’t clearly identified, or when there’s any sign of further movement.
The practical lesson is that paperwork is worth money. An afternoon spent tracking down the certificate of structural adequacy and the building control completion certificate can shift the price more than any amount of redecorating. If you’d like to talk through which documents you have and which you still need, we’ll tell you how each one affects the figure.
FAQs
Does underpinning devalue a house?
Usually by a small amount where the paperwork is complete and the house has been stable for years. The discount is larger where documents are missing, the work is recent or the cause of the subsidence isn’t clearly resolved.
Can you get a mortgage on an underpinned house?
In most cases, yes. Lenders want the structural engineer’s report, the certificate of structural adequacy and building control sign-off, and their surveyor will check for ongoing movement.
Is it hard to insure a house that’s been underpinned?
It’s harder than insuring an unaffected home. Specialist insurers cover underpinned properties, usually with higher premiums and a larger subsidence excess. Finding cover before marketing helps buyers.
Do I have to tell buyers my house was underpinned?
Yes. The property information form asks about structural work and insurance claims, and the buyer’s survey will reveal the underpinning anyway. Concealing it risks a misrepresentation claim.
What if I don’t have the underpinning paperwork?
Try the engineer, the contractor, the insurer who handled the claim and the council’s building control department. If it can’t be found, a fresh structural engineer’s report confirming stability helps, and a cash buyer can proceed without the historical file.
Will a cash buyer purchase an underpinned house with no guarantee?
Yes. The absence of a guarantee is reflected in the offer, but it doesn’t prevent a cash sale, because there’s no lender or insurer whose approval is needed before completion.