Getting Retrospective Building Regulations Approval

If building work at your home was completed without the proper building regulations notifications or sign-off, you are not automatically stuck. There is a formal legal route \u2014 known as regularisation \u2014 that allows you to apply to your local authority for retrospective building regulations approval after the work is finished. This guide explains how the process works, what it costs, how long it takes, and how it compares to the alternative of indemnity insurance.

Whether you are preparing to sell a property with an extension, loft conversion, or any other structural alteration that lacks a completion certificate, understanding your options early will help you avoid delays at the conveyancing stage.

What is retrospective building regulations approval?

The Building Regulations 2010 require that notifiable building work \u2014 including extensions, loft conversions, structural alterations, and certain electrical and heating installations \u2014 is approved and inspected by building control before and after the work is carried out. The local authority or an approved inspector issues a building control completion certificate once the finished work has been inspected and found to comply.

When work is carried out without the proper notifications \u2014 whether due to oversight, a rogue builder, or work by a previous owner \u2014 no completion certificate is issued. This creates a problem when selling, because the buyer's solicitor and mortgage lender will require evidence that the work was properly signed off.

Retrospective building regulations approval is the process of obtaining that sign-off after the fact. It is formally called a regularisation, and it is authorised by regulation 18 of the Building Regulations 2010. The result of a successful regularisation application is a regularisation certificate, which carries the same legal standing as a standard completion certificate.

Which types of work can be regularised?

Regularisation is available for any notifiable building work that was carried out after November 1985, when the Building Act 1984 came into force. This covers the vast majority of residential building work that sellers encounter, including:

• Single-storey and multi-storey extensions
• Loft conversions
• Garage conversions
• Removal of or alterations to load-bearing walls
• Installation of new boilers, heating systems, or unvented hot water cylinders
• Electrical work in kitchens, bathrooms, and outdoors
• Replacement of windows and external doors
• Alterations to drainage or drainage connections
• Structural repairs, underpinning, or alterations to the roof structure

For work carried out before November 1985, regularisation is not available, and indemnity insurance is usually the only option. Some local authorities may also decline regularisation applications for certain types of work \u2014 it is always worth confirming with your local authority building control department before proceeding.

How the regularisation process works

The regularisation process is administered by your local authority building control (LABC) department. Private approved inspectors cannot issue regularisation certificates \u2014 this route is available only through the local authority.

Step 1: Contact your local authority building control

Before submitting a formal application, it is worth calling or emailing your local authority building control team to discuss the work in question. Explain what was done, when it was completed if known, and that you are seeking retrospective approval. They can confirm whether they will accept a regularisation application, provide an indication of the fee, and advise on what supporting information they will need.

Important: Once you contact the local authority about the work, indemnity insurance is no longer available as an alternative. The insurer will treat any contact with the local authority as “notification” and will refuse to issue a policy. Make sure you have decided to pursue regularisation before making contact. If you are unsure whether regularisation or indemnity insurance is the better choice, speak to your solicitor first.

Step 2: Submit the regularisation application

The regularisation application is a specific form, separate from a standard building regulations application. You will typically need to provide:

• A description of the work that was carried out
• The approximate date the work was completed
• Any plans, drawings, or specifications that are available
• Photographs of the work where relevant
• The regularisation application fee

If no drawings exist for the work, you may need to commission a builder or structural engineer to produce a measured survey and drawings before submitting. This is an additional cost to factor in, particularly for extensions or loft conversions where the local authority will want to understand the scope of the work before inspecting.

Step 3: The inspection

Once the application is accepted, a building control surveyor will visit the property to inspect the work. Because the work is already finished, the surveyor cannot carry out staged inspections at key points during construction. Instead, they must assess the completed work in its current state.

For concealed structural or safety-critical elements, this may require opening up parts of the building. Common examples include:

• Removing sections of plasterboard or ceiling finishes to check steelwork, joist sizes, or fire-stopping
• Lifting floorboards to inspect floor joists, under-floor insulation, or drainage connections
• Exposing sections of the external wall or roof to verify insulation, structural ties, or cavity barriers
• Checking the depth and width of foundations, which may require excavating a trial pit

You are responsible for arranging and paying for the opening up and for making good afterwards. The extent of opening up required depends on the nature of the work and the surveyor's assessment of what is needed to verify compliance.

Step 4: Remedial work (if required)

If the inspection reveals that part of the work does not comply with the Building Regulations, the surveyor will specify what remedial work is needed. You must carry out the remedial work before the certificate can be issued, and a further inspection will take place once it is complete.

Common remedial requirements include improving insulation to meet current thermal standards, upgrading fire doors or fire-stopping, reinforcing structural elements, or addressing drainage or ventilation deficiencies. In some cases, particularly for older extensions or loft conversions built to lower historical standards, the cost of remedial work can be significant.

Step 5: Regularisation certificate issued

Once the local authority is satisfied that the work complies with the Building Regulations \u2014 either as originally built or following remedial work \u2014 they issue a regularisation certificate. This document confirms that the work has been retrospectively approved and is accepted by all mortgage lenders and buyer solicitors. It should be kept with your property documents and disclosed in your TA6 Property Information Form when you come to sell.

Costs of retrospective building regulations approval

The costs associated with regularisation fall into three categories: the application fee, the cost of opening up, and the cost of any remedial work required.

Regularisation application fees

Regularisation fees are set by each local authority and are typically charged at 1.5 to 2.5 times the standard building control fee for the same type of work. The following figures are indicative; actual fees vary by local authority and should be confirmed directly with your LABC team.

Opening up costs

The cost of opening up for inspection varies considerably depending on what needs to be exposed. Simple access \u2014 such as lifting floorboards or removing a section of plasterboard \u2014 might cost £200 to £600 for a builder to open up and reinstate. More extensive investigations, such as excavating a trial pit to check foundations, can cost £500 to £1,500. If the surveyor requires the opening up of multiple concealed elements, total opening up costs can exceed the regularisation fee itself.

Remedial work costs

Remedial work costs are the most unpredictable element of regularisation. For minor issues \u2014 such as adding additional insulation or upgrading a fire door \u2014 the cost might be £200 to £800. For more significant structural or safety issues, costs can run into thousands of pounds. If you are concerned about the potential for expensive remedial work, this is a factor to weigh when deciding between regularisation and indemnity insurance.

How long does retrospective building regulations approval take?

The timeline from submitting your regularisation application to receiving the certificate is typically 4 to 10 weeks, assuming no significant remedial work is required. If remedial work is needed, the total process can take 3 to 5 months or more.

This timeline has implications for sellers. If you are planning to sell your home and are considering regularisation, it is best to start the process before putting the property on the market. Waiting until a buyer has been found and solicitors are instructed risks causing delays to the transaction, as the buyer's solicitor will typically not agree to exchange until the regularisation certificate has been received.

If time is a constraint, indemnity insurance can be arranged within a few days \u2014 but remember that this option is only available if you have not already contacted the local authority. See our guide on building regulations sign-off missing for a full comparison of both routes.

Regularisation vs indemnity insurance: which is right for you?

Both regularisation and indemnity insurance are accepted solutions in UK residential conveyancing, but they serve different purposes and suit different circumstances.

Choose regularisation when:

• The work was completed within the last 12 months (the Section 36 enforcement window under the Building Act 1984 is still open)
• The work is structural or safety-critical and you want maximum reassurance for buyers and lenders
• You have sufficient time before listing the property
• The buyer's lender specifically requires a regularisation certificate
• You are confident the original work was well executed and unlikely to require expensive remediation

Choose indemnity insurance when:

• The work was completed more than 12 months ago and the enforcement window has closed
• You need a quick resolution and cannot wait 4 to 10 weeks for regularisation
• The work is low-risk (cosmetic alterations, replacement windows, straightforward boiler replacement)
• You are concerned that opening up for inspection may reveal expensive defects
• The buyer and their lender are willing to accept indemnity insurance

Retrospective approval and the property information forms

When selling a property, you are required to complete the TA6 Property Information Form, which asks specifically about building work and whether building regulations approval and completion certificates are available. You must answer these questions honestly; failing to disclose known building work is misrepresentation and can expose you to legal liability after completion.

If you have obtained a regularisation certificate, you should disclose the building work and confirm that a regularisation certificate is available. Keep the certificate with your property documents. If you have indemnity insurance rather than a regularisation certificate, disclose the work and confirm that indemnity insurance is in place.

The property certificate pack that your solicitor assembles for the buyer will include copies of any regularisation certificates or indemnity policies, along with the results of property searches and the completed protocol forms. Having these documents organised and ready before you market the property can significantly reduce delays once a buyer is found.

Planning permission and building regulations: separate requirements

It is important to understand that planning permission and building regulations approval are entirely separate legal requirements, even though both may apply to the same piece of work.

• Planning permission determines whether you are permitted to carry out the work at all \u2014 its size, location, appearance, and effect on the surrounding area. It is granted by the local planning authority.
• Building regulations approval determines how the work must be constructed \u2014 the structural, fire safety, drainage, ventilation, and energy efficiency standards. It is administered by building control (either the local authority or an approved inspector).

A project may need both, either, or neither. A rear extension within permitted development limits does not require planning permission but does require building regulations approval. A change of use of a building may require planning permission but not building regulations approval if no physical construction is involved.

If work at your property is missing both planning permission and building regulations sign-off, you need to address each issue separately. See our guide on planning compliance certificates for information on the planning side of this problem.

The cost impact on your sale

Missing building regulations sign-off rarely prevents a sale from proceeding, but it can affect both the sale price and the timeline if not handled proactively. The costs of selling a house can mount up when unexpected conveyancing issues arise, so it is worth addressing known issues before going to market.

If you have obtained a regularisation certificate before marketing, it removes a potential negotiating point for buyers and demonstrates that the property has been properly prepared for sale. If the issue only comes to light during conveyancing, buyers may use it as leverage to negotiate a price reduction \u2014 particularly if structural work is involved and they have concerns about the quality of the original build.

Obtaining retrospective building regulations approval before listing is one of the most effective things a seller can do to reduce the risk of sale fall-through or renegotiation.

Sources

• Building Regulations 2010, regulation 18 (regularisation) — legislation.gov.uk
• Building Act 1984, Section 36 (enforcement) — legislation.gov.uk
• Local Authority Building Control (LABC) regularisation guidance — labc.co.uk
• GOV.UK — Building regulations: apply for building regulations approval (Planning Portal)
• UK Finance Mortgage Lenders' Handbook — ukfinance.org.uk
• Law Society Conveyancing Protocol, 5th edition — lawsociety.org.uk
• Planning Portal — Do I need building regulations approval? — planningportal.co.uk

Frequently asked questions