Regularisation: fixing work done without building regs

Regularisation is a retrospective application to your local authority for building work carried out without approval. It is available for work done on or after 11 November 1985, the owner applies rather than the builder, and the work is assessed against the requirements that were in force when it was done rather than today's standards. The council can require you to open up finished work so it can be inspected, and the certificate at the end is discretionary.

That last point is worth absorbing early. Regularisation is a route, not a guarantee.

When you need it

Almost always at sale, and almost always unexpectedly.

A buyer's solicitor asks for the completion certificate for the loft conversion, the removed wall, the extension. There isn't one. Either the work predates the current owner and nobody ever asked, or a builder said they would deal with it and did not. From that point you have three options: regularisation, an indemnity policy, or renegotiating the price.

It also arises when you discover it yourself, part way through your own project, when building control asks about an opening someone made in 2012.

How it works

Regularisation sits in regulation 18 of the Building Regulations 2010, and the mechanics matter.

Only work on or after 11 November 1985. Anything earlier is outside the regulation entirely, which is usually good news rather than bad.

The owner applies, not the builder. This is your application, and the original builder's involvement is irrelevant to it.

The standard is historic, not current. The work is judged against the requirements in force when it was carried out. So a 2004 loft conversion is measured against 2004 insulation standards, not 2026 ones. This is the single most useful feature of the process and the one people do not expect.

The council can require opening up. It may require you to lay open the work for inspection, and to carry out tests or take samples. On a finished room that can mean lifting flooring, removing plasterboard, or exposing a beam and its bearings.

There are three possible outcomes, and only one is a certificate. The authority may be satisfied and issue a regularisation certificate. It may tell you what work is required to make the building compliant. Or it may conclude that it cannot determine what work is required, which happens where too much is hidden to assess.

The certificate is discretionary and qualified. Even where issued, it is evidence that the requirements have been met rather than conclusive evidence.

What it costs

Councils set their own charges under the Building (Local Authority Charges) Regulations 2010 on a cost-recovery basis, so there is no national regularisation fee. Charges are typically set by reference to what the original application would have cost, often with an uplift, and published schedules vary by authority.

For context on the underlying application charges, published schedules put a domestic extension up to 40 square metres at £700 to £1,300 including VAT across most of England, with inner London higher: Tower Hamlets £1,551.60, Islington £1,584, Camden £1,875.55.

We are not going to quote a single regularisation figure, because the basis differs between authorities and yours is the only one that matters. Ask your council for its current schedule.

The larger cost is usually not the fee. It is the opening up, and then the making good afterwards, plus any remedial work the authority requires.

Indemnity policies, and what they do not do

The alternative people reach for, often on a solicitor's suggestion, is a building regulations indemnity policy. It is worth understanding precisely what you are buying.

An indemnity policy covers the risk of enforcement action by the local authority. That is all. It says nothing about whether the work is safe, or whether it was built to a reasonable standard, and it will not pay to put bad work right.

Three things void it, and two of them are counterintuitive:

If the council has already refused to certify the work.

If you notify the council of the policy's existence. Contacting the authority about the work at all can be enough, which is why solicitors tell you not to.

If later building works are carried out without the insurer's consent.

So a policy is a way of managing a conveyancing problem, not a way of resolving a construction one. If the concern is that a beam might be undersized, an indemnity policy is the wrong instrument entirely.

Regularisation or indemnity: how to choose

The honest test is what you are worried about.

Choose regularisation where you want the work actually assessed, where you intend to stay and build on it, where the work is structural, or where a buyer or lender is asking for certification rather than insurance. It is the only route that produces a certificate.

An indemnity policy may be adequate where the work is old and minor, where the risk is genuinely just enforcement, and where the buyer's lender accepts one. It is quicker and cheaper.

Neither works if you have already contacted the council and been refused, which forecloses the insurance route, or if the work is so covered up that the authority cannot determine what would be required.

One thing that has changed and matters here: the comfort that unauthorised work becomes safe with age has gone. Section 35 of the Building Act 1984 became an either-way offence through the Building Safety Act 2022, which removed the magistrates' time limit, and the Planning Portal states there are now no time limits on prosecution. Prosecution remains unlikely on a domestic job. The point is that time no longer cures it.

Planning is different, and the two get conflated. Unauthorised development does become immune from planning enforcement after set periods. Our guide to why planning and building regs enforce differently sets out where each one bites.

What the council will want to see

Practical preparation, because the smoother version of this process is the one where you arrive with information.

Anything you have about when the work was done and by whom, because the date sets the standard applied. Any drawings, invoices, or structural calculations, even partial. Certificates from the competent person schemes, because Part P electrical work and FENSA or CERTASS windows are self-certified and those certificates may exist even where no building control application does.

Then expect a conversation about access. Where a beam is boxed in or a floor is finished, the authority has to decide whether it can be satisfied without seeing it. Volunteering a sensible opening-up proposal is usually better than being told to strip a room.

For structural work specifically, having an engineer look at it first is often worth the fee, because it tells you whether you are heading for a certificate or a remedial bill. Our guide to what a structural engineer costs covers published fees for that kind of inspection.

Doing it properly on new work

The way to never need this is unglamorous: get the completion certificate at the end of the job.

In England regulation 17 requires the authority to issue a completion certificate in all cases where, after taking all reasonable steps, it is satisfied the relevant provisions have been complied with, and to do so within eight weeks of your completion notice. The route you chose, building notice or full plans, does not affect that entitlement.

So the certificate is not a favour and it is not optional extra paperwork. Our guide to how building control inspections work sets out the notices and the stages that lead to it.

How Beams helps

Regularisation is a problem created at the end of somebody else's project. The builder finished, the money was paid, and the certificate was nobody's job.

So on a Beams project the notices, the inspection stages and the completion certificate are explicitly somebody's responsibility rather than an assumption. And where we are working on a house with unauthorised work already in it, we would rather find that at the survey stage than have it surface when you sell.

That is part of the commitments in a Beams contract: one agreed price, payments released against milestones, and 12 months on the workmanship.

Common questions

Can I get regularisation for very old work?
Only for work carried out on or after 11 November 1985. Earlier work falls outside regulation 18, which usually means there is nothing to regularise.

Will I have to bring the work up to current standards?
No. The work is assessed against the requirements in force when it was done, not today's. That is often a much lower bar, particularly for insulation.

Will they make me open up finished rooms?
They can. The authority may require the work to be laid open for inspection and may require tests or samples. How much depends on what can be established without it, which is why bringing drawings and calculations helps.

Is an indemnity policy as good as a certificate?
No, and it does a different job. It covers the risk of enforcement action only, says nothing about whether the work is safe, and is voided if the council has refused to certify or if you notify the council of the policy. A certificate is evidence of compliance.

Do I have to tell the council, or can I leave it?
That is your decision and it has consequences either way. Approaching the council forecloses the indemnity route. Not approaching them leaves the work uncertified, and there is no longer a time limit after which building regulations enforcement becomes impossible.

Where this information comes from

Regularisation, the 11 November 1985 date, the owner as applicant, assessment against the requirements in force when the work was done, the power to require laying open, tests and samples, the three possible outcomes, and the certificate as evidence but not conclusive evidence: The Building Regulations 2010, regulation 18

Completion certificates, in all cases and within eight weeks: regulation 17(1) and 17(2), as currently in force in England

Standard for work to existing buildings: regulation 4(3)

Enforcement and the removal of the time limit: Building Act 1984 section 35, as amended by the Building Safety Act 2022, and Planning Portal guidance

Charges set on a cost-recovery basis: Building (Local Authority Charges) Regulations 2010, and published council fee schedules including Camden, Islington, Tower Hamlets, Southwark, Greenwich, Redbridge, Sutton, Hounslow, Ealing, Havering, Wandsworth, Hillingdon, Bromley, Lambeth, Harrow and Hackney

Competent person schemes: Part P for electrical work, and FENSA and CERTASS for replacement windows

Indemnity policy terms vary between insurers and the points above are the common features rather than universal ones. Read the policy. Regulations differ in Wales, and this page describes England.