Approvals & sign-off · October 2026
Building regulations completion certificate: what it is and how to get one
The completion certificate is the document that proves your extension, loft conversion or structural work was inspected and met building regulations. It is one of the first things a buyer's solicitor asks for — here is how to make sure you get it, and what to do if work on your home was never certified.[1]
Written by Renovome · Last updated: 26 October 2026 · England & Wales (Scotland and Northern Ireland issue equivalent documents under separate systems)
Missing your completion certificate?
- Work was approved and signed off: ask the building control body that inspected it for a copy, with the property address and application reference if available.
- Work is finished but not signed off: contact that body to arrange the final inspection and confirm any outstanding documents.
- Work was done without approval: ask the local council about regularisation; it is not the same as replacing a lost certificate.[3]
- Issued by
- Council or registered approver
- When you get it
- After the final inspection
- When you'll need it
- Selling or remortgaging
What the completion certificate actually is
When building work that needs building regulations approval is finished, the building control body — your local council's team or a private registered building control approver — carries out a final inspection. If the work complies, they issue a completion certificate (councils) or a final certificate (private approvers). Both confirm the work was inspected and met the regulations in force at the time.[1]
It is not a guarantee of quality or a warranty — it confirms compliance with minimum standards for structure, fire safety, insulation, ventilation and drainage. But it is the only formal evidence that the work was checked at all.
Alongside it, you should also hold certificates from competent person schemes for specific elements: electrical work (for example NICEIC or NAPIT), gas work (Gas Safe), and replacement windows and doors (FENSA or CERTASS). Buyers' solicitors ask for these separately.[2]
Why it matters when you sell or remortgage
During a sale, the buyer's solicitor raises standard enquiries about any alterations. For work that needed building regulations approval, they will ask for the completion certificate. Its absence does not prove the work is defective — but it creates doubt at exactly the wrong moment:
- Delays: the buyer may insist on a regularisation application or further investigation before exchanging.
- Price pressure: some buyers use a missing certificate to negotiate the price down, or walk away entirely.
- Indemnity insurance: a common workaround is an indemnity policy, which covers the buyer against enforcement action — but it does not confirm the work is safe, and some lenders and buyers will not accept it for recent work.
- Remortgaging: lenders can ask for certificates when you remortgage, particularly for structural alterations and conversions.
The certificate costs nothing extra beyond the building control fee you have already paid — the only real cost of not having one comes later.[2]
How to make sure you get one
For a full plans application, GOV.UK says you will usually get a completion certificate within eight weeks of completion, provided the work complies. This is not a guaranteed turnaround for every application: confirm the inspection and paperwork requirements with your building control body.[3]
- Book the final inspection before the builder leaves site. The inspector needs to see the finished work while the builder can still fix anything that comes up.
- Resolve any issues the inspector raises — the certificate is only issued once the work complies.
- Chase the certificate in writing. It does not always arrive automatically; councils issue it on request after a satisfactory final inspection, and private approvers issue their final certificate to you and the council.
- File it safely with your planning documents, warranties and competent person scheme certificates — you will need the whole pack when you sell.
If you used a private approver and they cease trading before issuing the final certificate, the work reverts to the local council — contact them to arrange completion.[1]
New to the whole process? Our building control explained guide covers building notice vs full plans, typical fees and every inspection stage.
If the work was never certified
If you bought a home with an uncertified extension or conversion, or the paperwork was lost, you have three realistic options:
| Option | What it involves | When it works |
|---|---|---|
| Regularisation application | The council assesses the work retrospectively — this can mean opening up finished areas for inspection | Unauthorised work carried out after 11 November 1985; alterations may be needed before a regularisation certificate is issued |
| Copy certificate from the council | Councils keep records; if the work was approved but the certificate was lost, ask for a copy or a letter confirming the outcome | Work that was properly inspected at the time |
| Indemnity insurance | A one-off policy (often under £100) covering enforcement risk, usually arranged through the conveyancing solicitor | Older work where nobody has raised concerns — but it proves nothing about safety and isn't accepted in every case |
Regularisation fees are typically 20–50% higher than a standard application, and the council can require remedial work before certifying. Even so, for anything structural it is usually money well spent compared with a stalled sale.[3]
Your certificate checklist
- Before work starts: confirm which approvals apply and put the inspection stages in your written agreement with the builder.
- During the build: make sure no stage is covered up before the inspector signs it off.
- At completion: book the final inspection before final payment, and chase the certificate in writing.
- Afterwards: keep the certificate with your planning documents, warranties and trade certificates — your future self will thank you.
Planning a project now? Create your Renovome brief and approvals and sign-off stages are built into your programme from day one.
Sources and review date
Choosing a provider for new work in Manchester? Compare five local building control options and review sources. For a missing certificate on existing work, contact the body that handled your application first.
Certificate application guidance checked against GOV.UK on 26 October 2026. Rules and fees are set locally and change — always confirm with your council or a registered building control approver.
- [1] GOV.UK: Building regulations approvalAccessed 12 October 2026
- [2] LABC: completion certificates and selling your homeAccessed 12 October 2026
- [3] GOV.UK: Regularisation of unauthorised building workAccessed 12 October 2026
General information for England & Wales, not legal or professional advice. Scotland and Northern Ireland operate separate building standards systems.