What is a certificate of structural adequacy?
A certificate of structural adequacy, often shortened to CSA or COSA, is usually issued at the end of a subsidence claim. It normally records the cause of the movement, the repairs carried out and who carried them out, and confirms that, in the issuer's opinion, the property was structurally adequate when the claim was closed. It is not a guarantee or a warranty that the house will not move again.
Who issues a certificate of structural adequacy?
Normally the loss adjuster or engineer appointed by your buildings insurer, once the claim has been settled and the repairs are complete. If you made the claim, ask your insurer or the loss adjuster for it, quoting the claim reference. If it has been lost, they can often send a new copy. If the subsidence was repaired privately, without an insurance claim, there may never have been a certificate.
When you might be asked for one
- Selling a house that has had subsidence. The buyer's solicitor usually asks for the certificate issued when the claim was closed.
- Buying a house that has had subsidence. You, your lender or your surveyor will want evidence that the movement was dealt with.
- Arranging buildings insurance. Many insurers ask for a certificate, or another engineer's evidence, before they will cover a house that has had a subsidence claim.
- Remortgaging, when the valuer notes past movement or repairs.
If you cannot get a certificate: two ways we can help
A General Structural Inspection report
A current engineer's report may be enough for an insurer, a buyer or a lender. On a General Structural Inspection, from £540* for a standard mid-terrace house, our engineer inspects the main structure, looks at the cracking and any past repairs, and takes account of the history you can give us. The written report sets out the property's current condition and whether it appears stable, in a form you can send to your insurer. A single visit shows the house as it is on the day, so it cannot prove that movement has stopped. Check with the insurer first that a report will be accepted.
A year of crack monitoring, then our certificate
When an insurer or buyer wants evidence that the movement has stopped, we fix monitoring gauges across the key cracks and take readings over a full year. Much of London is built on clay, which shrinks in dry summers and swells again in winter, so twelve months of readings help show whether movement is seasonal or still progressing. If the readings show the structure is stable, we issue our certificate of structural adequacy for the condition of the property at the end of the year. If they show continuing movement, we explain what that means and what further investigation or repairs may be needed instead.
You can have both: the General Structural Inspection now, for the insurer or the sale, and monitoring to follow if more evidence is wanted.
What our certificate includes
- The property address and the parts of the building that were monitored.
- The dates of our visits, where the gauges were fixed and every reading taken.
- A summary of the history: the damage, its likely cause and any repairs, as far as the records show.
- Our opinion on the condition of the structure at the end of the monitoring.
- Its limits: what could not be seen and what it does not cover.
- The engineer's name, qualifications and signature.
What a certificate is not
- Not a guarantee. It records an engineer's opinion at a point in time. London's clay and its trees can cause new movement later, which no certificate can rule out.
- Not Building Regulations approval. Underpinning is building work under the Building Regulations and must go through Building Control, which issues its own completion certificate. A certificate of structural adequacy does not replace it.
- Not an underpinning guarantee or an insurance policy. Guarantees come from the contractor that did the work, or from an insurance-backed scheme.
How much does a certificate of structural adequacy cost?
If your insurer handled the claim, start with them: a copy of their certificate is usually the quickest route. A General Structural Inspection from us costs from £540* for a standard mid-terrace house. A year of crack monitoring, with our certificate at the end if the readings show the structure is stable, costs from £2,100*. The final price depends on the size of the house and how many cracks need gauges, and you get it in writing before you book. See our prices.
How it works
- Send us what you have. Any claim letters, details of the repairs, what your insurer or the buyer's solicitor has asked for, and a few photos.
- We recommend a route and price it. A General Structural Inspection, monitoring, or both, with the price in writing before you book.
- An engineer inspects. The report from a General Structural Inspection usually follows within 5 working days. If you choose monitoring, we fix the gauges on the first visit.
- Readings through the year. We return to read the gauges, and after twelve months you receive the full set of readings and, if they show the structure is stable, our certificate.
Common questions
Do I need a certificate of structural adequacy?
Only if someone asks for one. There is no legal requirement, but buyers' solicitors, lenders and insurers often ask when a house has had subsidence or structural repairs. If the house has no history like that, a structural survey is usually the better answer to questions about cracks.
Who can issue a certificate of structural adequacy?
Normally the loss adjuster or engineer acting for the insurer that handled the subsidence claim. Where that is not possible, an independent structural engineer can issue one on the evidence of monitoring, as we do after twelve months of readings. Our certificates are signed by an engineer with a master's degree in structural engineering. If your buyer, lender or insurer wants a chartered engineer's signature, tell us when you book.
Why does the monitoring take a full year?
Clay soils move with the seasons, so a few months of readings can catch only the shrinking or only the swelling. A full year covers both summer and winter, which is what shows whether a crack is simply opening and closing or is still getting wider.
How long is a certificate of structural adequacy valid for?
It does not expire, but it describes the house at the time it was issued. An older certificate is still useful evidence of the repairs. If it is many years old, or new cracking has appeared since, buyers, lenders and insurers may ask for a current inspection.
Can I sell a house without one?
Often, yes. A current engineer's report, or monitoring results, may answer many of the same questions a certificate would. Whether that is enough is for the buyer, their lender and their insurer to decide.
Does your certificate cover repairs the insurer carried out?
No. It covers the condition of the property, as shown by our inspections and a year of monitoring. We note what we could see of any repairs, but we cannot inspect hidden work such as underpinning, and we do not certify it.
Is it the same as a Building Control completion certificate?
No. Building Control's completion certificate confirms that work met the Building Regulations. A certificate of structural adequacy is an engineer's opinion on the structure. After underpinning, buyers' solicitors often ask for both.
