Certificate of Structural Adequacy: What It Is and Why Buyers Ask for It
The last document in a subsidence repair, and the first one a buyer's solicitor asks about. Here is what it certifies, what it does not, who can issue it, and what to do when an underpinned house comes without one.
In short: a Certificate of Structural Adequacy is the structural engineer's formal opinion, issued at the end of a subsidence repair or underpinning project, that the part of the building that was treated is structurally sound. It records the damage, the cause the investigation found, the stabilisation measures and the remedial works, and confirms that a competent contractor did the work, that the engineer designed or reviewed the scheme, that Building Regulations approval was obtained and that the works were inspected. It is not a guarantee; the guarantee comes separately from the contractor. Insurers, lenders and buyers' solicitors ask for it because it is the one document that shows the cause was found and dealt with, and a house that has it, together with its drawings and completion certificate, sells and insures like any other.
What the certificate is
Subsidence repairs end with three questions from three different people. The insurer wants to know it can safely continue cover. The lender wants to know the property remains good security. The next buyer's solicitor wants to know what was wrong, what was done and who stands behind it. The Certificate of Structural Adequacy exists to answer all three at once, and the form it takes has been standardised across the subsidence industry for long enough that everyone involved knows what to expect from it.
It is a statement of professional opinion by the engineer, or other suitably qualified expert, who investigated the movement, specified or reviewed the remedial works and inspected them as they were built. That is the source of its value and also its limit: the certifier is saying that, having seen the cause, the design and the construction, they are satisfied the treated part of the building is stable, and they are putting their professional name and their indemnity insurance behind that opinion. They are not promising that nothing will ever move again, and the document says so.
When it is issued
At the very end. The certificate is the last step in a remedial contract, after the works are complete, any defects have been put right, the accounts have been agreed and paid and the contractor's guarantee has been issued. Where the investigation concludes that no major structural works are needed, for example where a drain repair or tree management has stabilised the building and only crack repairs follow, the engineer can issue a certificate at that stage on the strength of the investigation and monitoring alone. Either way it comes with the paperwork that supports it, described below.
What it records and confirms
| Section | What the certificate says |
|---|---|
| The property and the owner | Address and the name of the owner for whom it is issued |
| The damage | A general description of the damage the property sustained, cross-referenced to the investigation report |
| The cause | The cause of the movement as established by the investigation: for example clay shrinkage influenced by a named tree, or a leaking drain at a stated location |
| Stabilisation measures | What was done to remove or control the cause: drain repair, tree crown reduction and the regime to maintain it, and so on |
| Remedial works | The structural works carried out, such as partial underpinning of a stated length of wall, with reference to the as-built drawings and specification |
| The contractor | Confirmation that, to the best of the engineer's knowledge, the contractor was competent to carry out the work |
| The design | Confirmation that the engineer designed the works with professional skill and care, or, where the contractor designed them, reviewed the adequacy of that design |
| Approvals | Confirmation that Building Regulations approval was obtained, with copies of the approval and completion certificate attached |
| Inspection | Confirmation that the engineer inspected the works during the contract and was satisfied with what was seen at the times of the visits |
| Scope | That it covers the structural works that contribute directly to stability, not the cosmetic repairs, and that it is a professional opinion, not a warranty |
Typical content; the exact wording varies between practices and insurers. Ask to see a specimen before the works start so the certificate you receive is the one you expected.
What it is not
- Not a guarantee. It is an opinion, backed by the engineer's professional indemnity insurance. The guarantee is a separate document from the contractor, ten years being the norm today, and it is worth only as much as the company behind it unless it is insurance-backed. Ask for both.
- Not a survey of the whole house. It covers the part of the building that was investigated and treated. A wall on the other side of the house that was never in question is outside it.
- Not a cosmetic sign-off. Repointing, replastering and decoration are outside its scope; any argument about the standard of those is a contract matter, not a structural one.
- Not a waiver. It does not reduce the owner's rights against the contractor or the designer if the works later prove defective.
- Not permanent. It has no expiry date, but it describes the building at the date of issue on the assumption that the cause has been dealt with and the property will be reasonably maintained. A tree allowed to grow back unmanaged, a new drain leak or fresh cracking calls for a new inspection, not reliance on an old certificate.
Why insurers, lenders and buyers ask for it
Insurers will normally continue cover after subsidence repairs, and the industry's own guidance is that where a property has been properly investigated and repaired and a Certificate of Structural Adequacy is available there should be no technical reason for any insurer to refuse or withdraw cover. That matters most at the moment an owner tries to move insurer, when the new company is entitled to ask why it should take on a house with a history; the certificate and its bundle are the answer. Our guide to subsidence insurance claims covers the rest of that process.
Lenders apply a simpler test: is the property stable, and would it be readily saleable if they had to take possession. Many period houses are distorted and mortgageable at the same time; what a valuer wants is evidence that the movement has stopped, and the certificate is that evidence.
Buyers, through their solicitors, raise standard enquiries about subsidence, underpinning, claims and guarantees. A seller who can produce the certificate, the investigation report, the drawings, the Building Regulations completion certificate and the contractor's guarantee closes those enquiries in a single reply. A seller who cannot will usually face a request for an engineer's report, a delay and sometimes a renegotiation, which is why the last piece of advice at the end of every subsidence repair is the same: keep everything.
The bundle that goes with it
The certificate is the cover sheet on a file. The file should contain the initial appraisal, the monitoring results and the investigation report that established the cause; the repair specification and, for underpinning, the design drawings and calculations; the Building Regulations approval and completion certificate; the as-built drawings showing exactly where the underpinning is and how deep it goes, with any variations from the design; the contractor's guarantee; and the arboricultural report and pruning regime where a tree is being managed. Scan it, keep the originals, and hand the lot to the next owner. Our guide to underpinning explains what the drawings will show.
When the house has no certificate
A great many London houses were underpinned in the boom years of the 1980s and 1990s, and the paperwork has not always followed them through three or four changes of owner. If you are buying or selling one, or you own one and want to sort it out before you sell, the sequence is this. First, gather what exists: Building Control records for the address, which the council holds and which usually show at least that an application was made; the previous owner's or seller's file; the insurer's claim file if the works were an insurance claim; and any contractor's guarantee, which may still be traceable through the contractor or the guarantee insurer.
Then commission a structural engineer's inspection and report. The engineer examines the property for any evidence of continuing movement, reads the crack pattern against the history, takes a level survey along the brick courses where there is doubt, and where nothing at all is known about the underpinning may open a trial pit to confirm that it exists, its depth and its condition, with a short period of monitoring if the picture is unclear. The report that follows states the engineer's opinion of the property's current structural condition. It is not a Certificate of Structural Adequacy, because an engineer cannot honestly certify works they did not investigate, design or see built, and any engineer who offers to should be avoided; but a clear report on current condition from an independent engineer is what lenders, insurers and buyers generally accept in its place. Indemnity insurance, which conveyancers sometimes offer instead, covers the legal risk of missing paperwork and says nothing about the structure.
Where EMA Structures fits
On subsidence repairs and underpinning that we investigate, design and inspect, the certificate is part of the job: we issue it with the as-built drawings, the specification and the approvals once the works are complete and signed off. For an underpinned house without one, we provide a full structural survey with a written report at £495 to £1,500 + VAT depending on the size of the property. For that fee you get: a review of whatever paperwork exists, Building Control records, any contractor's guarantee, the old claim file; an engineer's inspection of every elevation and the inside of the property for signs of past or continuing movement, with a record of the cracks and how they relate to the underpinning; a level survey along the brick courses where there is any doubt about movement; and a written report giving our opinion of the property's current structural condition and whether the underpinned part is performing, which is what a lender, an insurer or a buyer's solicitor needs. A trial pit to confirm the underpinning exists and its depth, and any period of monitoring, are quoted separately and only where the report cannot be given without them. The survey can be booked on its own or as part of our pre-sale structural review. Send us what paperwork you have and photographs of any cracks, and we will tell you what the property needs.
General guidance on UK practice as at September 2026. The form and wording of certificates vary; a certificate or report is an engineer's opinion on the evidence available at the date of issue and is not a guarantee. Fees exclude VAT.
Certificate questions
What is a Certificate of Structural Adequacy?
A document issued by the engineer at the end of a subsidence repair or underpinning project stating their professional opinion that the part of the building that was treated is structurally adequate. It records the damage, the cause found by investigation, the stabilisation measures and the remedial works, and confirms that a competent contractor was used, that the engineer designed or reviewed the scheme, that Building Regulations approval was obtained and that the works were inspected. It is a considered opinion, not a warranty or guarantee.
Who can issue a Certificate of Structural Adequacy?
The engineer, or other suitably qualified expert, who investigated the movement, designed or reviewed the remedial works and inspected them during construction, normally a chartered or incorporated structural or civil engineer. It cannot honestly be issued by someone who had no involvement in the works, because its value lies in the certifier having seen the cause, the design and the construction. An engineer coming to a previously underpinned house later can inspect and report on its current condition, which is a different document.
Is a Certificate of Structural Adequacy a guarantee?
No. It is the engineer's professional opinion based on the investigation, design and inspections, and it is backed by the engineer's professional indemnity insurance rather than by any promise to put things right. The guarantee comes separately from the contractor, typically for ten years and ideally insurance-backed. The two documents do different jobs and a buyer's solicitor will usually ask for both, together with the Building Regulations completion certificate.
Do I need a Certificate of Structural Adequacy to sell a house that has been underpinned?
There is no legal requirement, but in practice a sale of an underpinned house goes far more smoothly with one. Buyers' solicitors raise enquiries about past subsidence and underpinning as a matter of routine, valuers and lenders apply a test of continued stability, and insurers ask about previous claims at every renewal. A certificate, with the investigation report, the drawings, the Building Regulations completion certificate and the contractor's guarantee, answers all of them at once. Without it, expect a buyer to ask for a structural engineer's report and possibly a price reduction.
The house was underpinned years ago and there is no certificate. What can I do?
Gather what exists first: Building Control records for the address, the seller's or previous owner's paperwork, the insurer's claim file and any contractor's guarantee. Then commission a structural engineer's inspection and report. The engineer will examine the property for evidence of continuing movement, may take a level survey, and where nothing is known about the underpinning may open a trial pit to confirm it exists, its depth and its condition, with a short period of monitoring if the picture is unclear. The resulting report states the engineer's opinion of the property's current structural condition, which is what lenders and buyers generally accept in place of a certificate that was never issued.
How long does a Certificate of Structural Adequacy last?
It has no formal expiry. It certifies the works and the building's condition at the date it was issued, on the basis that the cause of movement had been dealt with and that the property would be reasonably maintained and not altered. Its weight naturally reduces with time and with events: a new cause, such as a tree allowed to grow back unmanaged or a new drain leak, or new cracking, would call for a fresh inspection rather than reliance on the old certificate.
Underpinned house, missing paperwork?
Send us whatever documents you have and photos of any cracks, and we will tell you honestly what the property needs before it goes on the market or through a mortgage valuation.