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Guidance

Apply for a completion certificate for mobile communications mast work

How to apply for a completion certificate after installing a mobile communications mast on the rooftop of an existing higher-risk building in England.

Applies to England

This guidance is for contractors and installers carrying out mobile communications mast work on the rooftop of an existing higher-risk building in England. A higher-risk building (HRB) has at least:

  • 7 storeys or is at least 18 metres high
  • 2 residential units or is a hospital or a care home

Check if you need building control approval

You must apply for building control approval from the Building Safety Regulator (BSR) if the mast work is part of other work carried out at the same time, including:

  • roof refurbishments
  • work to plant and equipment that serves the building rather than the mast

Before you apply

You must apply for a completion certificate from BSR after completing mobile communications mast work. This includes:

Related work may include:

  • structural components, including access infrastructure
  • cable routes
  • penetrations
  • electrical connections
  • fire stopping, weatherproofing and insulation

Before carrying out the work, you must have prior written approval from the relevant person. This could be the:

  • accountable person for each part of the building where work is taking place
  • building owner or person responsible for managing the building

All completed work must comply with building regulations, including:

  • competent professionals planned, managed and carried out the work
  • appropriate fire stopping, weatherproofing and soundproofing
  • the use of compliant products and materials

If you carry out work under the dispensation, your existing duties for the building’s golden thread and mandatory occurrence reporting still apply.

Apply for a completion certificate

You must apply for a completion certificate when the work is completed.

Apply by emailing building-control.applications@buildingsafety.gov.uk using the subject line ‘Mobile mast gateway 3’.

BSR will send you an application form to complete. You will need to provide:

  • application name
  • building name
  • applicant details for the client or agent
  • principal contractor details
  • principal designer details
  • building address, or Easting and Northing coordinates
  • description of the completed work
  • building information relevant to the work
  • date the work started
  • date the work was completed

Your application must include these supporting documents:

  • plans and supporting information to show how the work complies with building regulations
  • a signed statement from the client confirming that, to the best of their knowledge, the completed work complies with building regulations
  • a statement signed by both the client and the relevant person confirming building information has been provided and received
  • a notice stating the completion date
  • a site plan at a scale of at least 1:1250
  • compliance declarations signed by the principal contractor and principal designer, where appointed
  • if an agent is applying, a client-signed statement authorising the application and confirming the information is correct
  • a signed statement confirming the work meets the criteria set out in the dispensation

You must also complete a declaration confirming the information is complete and correct.

Charges

Charges for applying for a completion certificate are set out in the BSR charging scheme.

After you apply

BSR will assess whether the:

  • work is complete
  • work complies with building regulations
  • supporting documents are complete and accurate

If BSR is satisfied that the requirements have been met, it will approve the application and issue a completion certificate.

If BSR needs more information, it may ask for further evidence to show that the work complies with building regulations.

If BSR rejects your application, it will explain why.

Updates to this page

Published 22 September 2026

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