Retrospective Building Regulations approval for structural work
If a wall was removed, a loft converted or an extension built without Building Control approval, the usual fix is a regularisation application to your council. Here is how it works and where an engineer fits in.
Can you get Building Regulations approval after the work is done?
Yes, in most cases. Where work that needed Building Regulations approval was carried out without it, the owner can apply to the local authority's Building Control for a regularisation certificate. The council inspects the work, asks for evidence that it complies, and issues the certificate once it is satisfied. For structural work, that evidence nearly always means calculations plus some opening up, so the hidden parts can be seen.
Regularisation is handled by the local authority, not by a private building control body, and it is intended for work that has already been completed. If the work is still in progress, a normal application is usually the right route instead. Your council will confirm which applies and what its fee is. Expect it to be higher than the fee for an application made before the work started.
The process is not a rubber stamp. Building Control can ask for work to be exposed, altered or in some cases rebuilt if it does not comply, so it pays to go in with a clear, evidenced picture of what was actually built.
When the question usually comes up
Most of the cases we see surface during a sale. A buyer's solicitor asks for the completion certificate for a knocked-through kitchen or a loft bedroom, and there isn't one. Others come to light when an owner plans further work and Building Control asks about earlier alterations, or when a lender or insurer queries a comment in a survey. Typical examples include:
Indemnity insurance is sometimes offered as a quick alternative during a sale. It may cover the legal risk of enforcement, but it says nothing about whether the structure is safe, and it is often invalidated once the council has been contacted. If there is any doubt about the structure itself, answer the engineering question first.
- A load-bearing wall removed between front and rear reception rooms
- Chimney breasts taken out at ground floor with the stack left in place above
- A loft boarded out and used as a bedroom, or a full loft conversion
- A rear extension built by a previous owner with no paperwork
- A garage converted into a habitable room
What Building Control will want to see
For structural alterations, Building Control needs to be satisfied that the work meets Building Regulations Part A, which deals with structure. In practice that means evidence of the following:
Other parts of the regulations matter too, such as fire safety, insulation, ventilation and drainage, and the council will check those as well. The structural part is often the hardest to prove, simply because it is hidden behind plaster, under floorboards or below ground.
- The size and grade of any steel beams, and how they are connected and supported
- Padstones or bearings under beam ends, and what the masonry beneath them is like
- Foundations, both for extensions and for any posts carrying concentrated loads
- Fire protection to steelwork, where the layout requires it
- Calculations showing that each member is adequate for the loads it carries
Opening up: exposing what was built
Calculations alone are not enough if nobody knows exactly what is behind the finishes. The usual approach is targeted opening up: small, planned openings at the points that matter, rather than wholesale demolition.
For a removed wall, that typically means cutting a small hole in the ceiling to see the beam size and connections, and exposing each end to check the bearing and padstone. For a removed chimney breast, it means confirming how the breast or stack above is now supported. For an extension, a trial pit beside the wall shows the foundation depth and the ground it sits on. On London Clay with trees nearby, that depth matters a great deal.
We agree the locations with you beforehand, so the builder or decorator can make good efficiently afterwards. Where several openings or wall scanning are needed, our structural investigation and opening-up service covers the wider exercise.
How an engineer's assessment fits in
A retrospective structural assessment brings the evidence together. We inspect the completed works, record what the opening up shows, check the members by calculation and set out any remedial work needed. It starts from £600 + VAT, with the council's own fees charged separately. All our structural inspection reports are signed off by a chartered engineer who is a Member of the Institution of Civil Engineers (MICE).
We send the report and calculations to Building Control and liaise with them, so any questions are answered by the engineer who did the checks. Often the outcome is simply that the work is adequate as built. Sometimes it needs modest changes before the council will sign it off.
Common outcomes and remedial work
Where something falls short, the fix is usually smaller than people fear. Typical remedies include:
Once any remedial work is complete and inspected, Building Control can issue the regularisation certificate. Keep it with the report and calculations, because together they answer the question a future buyer will ask. Our guide to Building Control and structural work explains how the normal approval route works for any further alterations you plan.
- Adding or upgrading padstones under the ends of a beam
- Bolting a second steel section alongside an undersized beam, or adding a post
- Providing proper support to a chimney stack left above a removed breast
- Applying fire protection to exposed steelwork
- Strengthening or underpinning a shallow foundation, in rarer cases
Practical steps before you start
Gather whatever information exists: drawings, builder's invoices, photographs taken during the work, steel delivery notes or an old engineer's calculation. Each of these can reduce how much opening up is needed. Then contact the council to confirm the regularisation process and fee, and tell your conveyancer what you are doing if a sale is under way.
Every job starts with a fixed fee confirmed in writing before any work starts, and our typical turnaround is 10 working days, confirmed in writing with the fee. If you are not sure whether the work needed approval in the first place, our guide on removing a wall is a useful starting point.
Frequently asked questions
How long does retrospective Building Regulations approval take?
It depends on the council and on how much needs to be exposed or corrected. The engineering part is usually the quickest step: our typical turnaround is 10 working days once we have inspected, confirmed in writing with the fee. The council then reviews the information, inspects and may ask for further opening up or remedial work. Ask your Building Control office about its current timescales at the outset.
Can I sell a house without a completion certificate for structural work?
Often yes, but buyers' solicitors and lenders will ask questions, and some buyers will renegotiate or withdraw. Indemnity insurance is a common shortcut for the legal risk, yet it says nothing about whether the structure is safe. Starting a regularisation application, backed by an engineer's assessment of the work, gives a buyer much stronger reassurance than a policy alone.
Will I have to tear the work out?
Rarely. In most cases targeted opening up shows enough to prove the work is adequate, or to define a modest fix such as a new padstone, an extra post or added fire protection. Removal is generally only needed where the work is clearly unsafe or cannot reasonably be made to comply. The sooner the work is checked, the sooner you know where you stand.
Can a private building control body regularise unauthorised work?
No. Regularisation of completed work that never had approval is handled by the local authority's Building Control. Private building control bodies deal with work before and during construction. If your work is still under way, the council may advise a normal application instead. Either way, an engineer's calculations and report can be submitted to whichever body is handling the work.
What if the work was done by a previous owner?
The route is the same. You apply as the current owner, and Building Control assesses the work as it stands today. The difficulty is usually missing information, since nobody remembers which beam was installed or how deep the foundations went. That makes opening up more important. Any old drawings, photographs or invoices left with the house documents are worth finding first.