After BSR approval: notices, changes and the completion certificate for flat works

Getting Building Safety Regulator (BSR) approval for work to a flat in a higher-risk building (HRB) feels like the finish line. It is not. Approval comes with conditions on how you start, how you handle changes on site and how you finish. If you skip these steps, you can end up with completed work and no completion certificate. This guide walks through what happens between approval and sign-off for building work to an existing HRB in England. It is general information, not legal advice or a building control decision.

The short answer

• Tell BSR before you start. Give a notice of intention to start at least 5 working days before work begins, then a commencement notice within 5 working days of reaching commencement (GOV.UK).
• Build what was approved. Every change goes in a change control log. Some changes must be notified to BSR first, and major changes need BSR approval before that part of the work goes ahead.
• Apply for a completion certificate when the work is finished. BSR inspects the completed work and reviews your records before deciding.

Before work starts

Check for requirements on your approval

BSR can approve an application outright, or "approve with requirements". If yours has requirements, work can only go ahead on the parts the requirements do not affect until they are met (GOV.UK). Read the decision notice carefully before you book trades.

Give the start notices

For work to an existing HRB, the client must give BSR:

• a notice of intention to start work at least 5 working days before starting
• a notice of commencement within 5 working days of the work reaching "commencement", as defined in the Building Regulations 2010
• notifications at the points set out in your inspection schedule, as the work progresses

These notices are free (GOV.UK). Agree with your principal contractor who will send them and when, so nothing is missed in the rush to get going.

Do not let the approval lapse

If the work has not reached commencement within 3 years, the approval lapses and you lose it (GOV.UK). This matters for flats bought with a long-term plan, or where works are delayed while leases or funding are sorted out.

During the works: change control

The approved application includes a set of agreed documents: drawings, the building regulations compliance statement, the fire and emergency file and the control plans. GOV.UK says you must comply with those agreed documents throughout the build (GOV.UK).

Real projects change. Once walls are opened up, the structure may not be what the drawings assumed, a product may become unavailable, or the client may change their mind about the layout. BSR sorts changes into three types:

• Recordable changes. Like-for-like or higher-specification replacements, for example. You record them in the change control log.
• Notifiable changes. You must tell BSR before starting any work involving a notifiable change. BSR may ask for more information, but you do not have to stop work while you answer.
• Major changes. These "undermine the basis by which the project was approved". You must stop the related work, submit a major change application and have BSR approve the change before going ahead.

Every change, whatever its type, goes in the change control log. Your change control plan, submitted with the original application, says how the team will identify, record and handle changes. Follow it.

BSR will take up to 6 weeks to decide a major change application unless a longer period is agreed. It can approve the change, approve it with requirements, or reject it. If it is rejected, you must not start the work it covers (GOV.UK). A change control application currently costs £195, plus BSR's hourly charges (GOV.UK).

Practical point: in a flat refurbishment, a "small" design change can affect fire safety. Moving a door, changing a ceiling or rerouting services through a fire-separating wall may sound minor, but it can change how the flat performs in a fire. Ask your principal designer which category a change falls into before you commit to it on site.

Finishing: the completion certificate

When building work to an existing HRB is complete, you must apply for a full completion certificate (GOV.UK). You can only apply for a partial completion certificate if you submitted a partial completion strategy with your original application. In a single-flat project, that is unusual.

What goes with the application

GOV.UK lists the information BSR needs, including:

• the latest versions of the drawings
• the construction control plan, change control plan and mandatory occurrence reporting plan
• the building regulations compliance statement and the fire and emergency file
• a summary of the completed work, with the completion date
• the change control log

You also need a signed statement from the client confirming that information about the work has been handed over to the building's accountable person (or principal accountable person) and, where relevant, the responsible person under fire safety law. This keeps the building's "golden thread" of information up to date (GOV.UK). In practice, the freeholder or managing agent gets an updated record of your flat's layout, fire safety measures and products used.

What BSR does

BSR inspects the completed work and reviews the change control log and any changes submitted during the project (GOV.UK). If it is satisfied, it issues the certificate. If not, the application is rejected and no certificate is issued. You can ask BSR to review the decision, then appeal to the First-tier Tribunal.

Two more things can hold up a certificate:

• Overdue charges. BSR will not issue a completion certificate while you owe it charges. A full or partial completion certificate application currently costs £234, plus hourly charges (GOV.UK).
• The Building Safety Levy. Where the levy applies, BSR cannot issue a completion certificate until the council has confirmed it has been paid or that no charge is due. The levy is aimed at new residential development, but ask your principal designer to confirm the position for your project.

Why the certificate matters to you

The completion certificate is your evidence that the work was signed off by the building control authority. Without it, you may struggle when you sell or remortgage, and your freeholder may not treat the licence conditions as met. Keep it with your lease papers, the approved drawings and the change control log.

A checklist from approval to sign-off

1. Read the decision notice and note any requirements.
2. Send the notice of intention to start at least 5 working days before work begins.
3. Send the commencement notice within 5 working days of reaching commencement, and inspection notifications at the agreed stages.
4. Keep the change control log up to date from day one, and check each change's category before acting on it.
5. Hand over the building information to the accountable person and get the client's signed statement ready.
6. Apply for the completion certificate when the work is finished, with the full document set.

If you are still at the earlier question, whether your flat works need BSR approval at all, the BSR screener gives you a first view in a few minutes. Our guide How long does BSR approval take? covers the decision stage.

Sources

• Building control approval for higher-risk buildings, GOV.UK (Building Safety Regulator), updated 1 October 2026
• Making changes to a higher-risk building project, GOV.UK, updated 1 October 2026
• Applying for a completion certificate, GOV.UK, updated 1 October 2026
• Manage a building control application for a higher-risk building, GOV.UK (charges), updated 1 October 2026
• Keeping information about a higher-risk building: the golden thread, GOV.UK