Guide

Building control approval for works in a high-rise building.

If you are altering a flat in a tall residential building, you may need building control approval from the Building Safety Regulator before work starts. This guide explains the application documents and where to check the procedure. Reviewed 6 October 2026 against the linked official guidance; confirm the precise building and work with a competent adviser.

The short version

Who needs building control approval

A higher-risk building is one that is at least 18 metres tall, or has at least 7 storeys, and contains two or more residential units. Building work to an existing higher-risk building needs approval from the Building Safety Regulator before it starts, unless it is exempt work, competent person scheme work, qualifying fibre-optic cabling work or an emergency repair under the relevant procedure. GOV.UK: building control approval for higher-risk buildings

Work inside a single flat can require approval. The building status, precise work and applicable exceptions must be checked; a small job is not automatically exempt. Qualifying fibre-optic work has separate criteria and notification requirements in the linked BSR guidance.

The application is made by the client, the person the work is being carried out for, which for a flat is usually the leaseholder. Someone may apply on the client's behalf, but the client stays legally responsible throughout. Regulation 11, SI 2023/909 (the client is the applicant)

The dividing line

Category A and category B, in plain words

The law splits the work in two. The category decides how many documents the application must carry, and BSR says it is likely to reject an application made under the wrong category. Regulation 12(6), SI 2023/909 (the category test)

Category A

Work that changes external size or the number of storeys, changes the number of homes, alters an escape route, touches an external wall, changes the internal layout, affects the passive or active fire safety measures, or affects the common parts.
Pulls in the full set of prescribed documents below. Most in-flat renovation trips one of these limbs.

Category B

Any work that does not fall into category A.
Needs the core application and plans, plus fire safety compliance information where the fire safety requirements apply, and fewer of the prescribed documents.

Uncertainty is not a confirmed category. Check the applicable criteria with the competent designer. ClearPath keeps unanswered facts visible and retains a conservative document set while they remain unresolved. A consultation response is not a substitute for checking the rules currently in force. GOV.UK: categorisation consultation and response

What the law asks for

The prescribed documents

For category A work, the application must carry all of these. The Building Safety Regulator publishes no templates, so applicants build each one from the guidance. GOV.UK: preparing information for an application

Application and building description. Who you are, the building, and a description of the proposed work.
Location plan at 1:1250 or better. The building, its boundaries, and the street.
Plans that show compliance. Existing and proposed drawings, clearly labelled.
Competence declaration. The client's signed statement that the appointed people were checked. Names real appointments; it cannot be filled with unnamed roles.
Construction control plan. How the work is planned, managed and monitored, with a schedule of who is appointed. This is not a CDM construction phase plan.
Change control plan. How changes are identified, decided, recorded, and when the regulator must be told.
Mandatory occurrence reporting plan. How safety occurrences are reported through the system the principal designer and principal contractor run.
Building Regulations compliance statement. The approach taken to meet each applicable requirement, with the standards followed. A competent person prepares the compliance content.
Fire and emergency file. The building safety risks considered and how people are kept safe. A competent person prepares this; ClearPath does not.
Partial completion strategy. Only where part of the building is occupied before the work is finished.
Client agreement statement. Only where an agent applies for the client, confirming the client agrees and that the information is correct.

Category B work needs the core application and plans, plus fire safety compliance information where the fire safety requirements apply, and only such of the documents above as the applicant considers appropriate. The regulator can still ask for any of them. Schedule 1, SI 2023/909 (what each document must contain)

Money and time

Fees and honest timelines

£195 on submission, plus £156 per hour of the regulator's assessment time, plus any third-party costs. Payable by the client. The £195 charge is not refundable if the application is declined.
8 weeks by statute from the date the regulator receives a valid application, or longer by written agreement. This is not a guaranteed completion date. Complexity, information requests and an agreed extension can affect assessment; confirm current expectations with BSR.
The Building Safety Levy applies from 1 October 2026. Check the applicable charging conditions, exemptions and information requirements rather than assuming that no charge means no levy information is needed. GOV.UK: Building Safety Levy guidance

BSR charging scheme 2026 to 2027 Regulation 13, SI 2023/909 (the 8 week determination period)

Where applications fail

The validation trap

Validation is a completeness check. An application is valid only if it complies with the prescribed list. If a required document is missing, the regulator may ask for the missing information, or it may reject the application with reasons, and a rejected application in practice means starting again with a fresh application. Validity is decided by the regulator, and no tool can promise it. Regulation 13, SI 2023/909 (valid means complies with regulation 12)

Before submitting, review the precise documents requested, the appointed people and the work scope. ClearPath makes omissions and conflicts easier to inspect; it cannot decide whether the regulator will validate the application.

Separately, fire safety can also be raised at planning stage for these buildings. If that is where you are, our fire safety and planning guide covers the planning side.

What ClearPath does and does not do here

ClearPath is a readiness tool. It checks that the prescribed documents are present, that each is structured the way the law asks, and that the pack is internally consistent, all against the sourced list. It drafts the formulaic documents for you to edit, and it flags the parts that need a competent person.

It does not submit for you, and it is not the Building Safety Regulator.
It does not act as the applicant or agent.
It does not give building control, fire safety, or fire engineering advice, and it does not assess whether any fire safety approach is adequate.
It does not decide the category for you, and it does not predict whether the regulator will validate or approve.

This page is signposting, not advice. For work to a higher-risk building, speak to an architect or building control professional experienced with these buildings, and a fire engineer for the fire safety content.

Sources

Where this comes from

Every official page below was checked live on 10 July 2026. The governing instrument is The Building (Higher-Risk Buildings Procedures) (England) Regulations 2023, SI 2023/909.

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