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Boiler Installation Certificate: How to Get One and What to Do If It's Missing

Bhavesh Ramburn

What is a boiler installation certificate?

A boiler installation certificate is the formal confirmation that a new or replacement boiler has been installed in compliance with Building Regulations. In England and Wales the relevant regulations are Approved Document G (Sanitation) and Approved Document L (Conservation of fuel and power); in Scotland the equivalent is the Building (Scotland) Regulations and the technical handbooks.

There are two distinct documents often called “boiler installation certificates”, and they are not interchangeable:

  1. Building Regulations Completion Certificate — issued by your Building Control body (either the local authority or a private Approved Inspector) after a competent person self-certifies the work or after a Building Control inspection. This is the certificate that proves your boiler installation complied with the Building Regulations.
  2. Gas Safe Register certificate — issued by the engineer or installation company on completion, confirming the gas work itself was carried out by a Gas Safe registered engineer in compliance with the Gas Safety (Installation and Use) Regulations 1998.

You should receive both when a gas boiler is installed. Each plays a different role: the Building Regulations certificate proves the install was compliant as built; the Gas Safe certificate proves the engineer was qualified to do the work.

Building Regulations vs planning permission: the two systems

A boiler installation is a Building Regulations matter, not a planning permission matter. The two regimes run in parallel but answer different questions:

  • Planning permission — governed by the Town and Country Planning Act 1990. Run by your Local Planning Authority (LPA). Concerned with the use of land and buildings, the appearance of development, and its impact on neighbours and the environment. Replacing a boiler in the same location is normally Permitted Development under Class G of the GPDO 2015 and does not require a planning application.
  • Building Regulations — governed by the Building Act 1984. Run by Building Control bodies. Concerned with structural safety, fire safety, energy efficiency, ventilation, and sanitation. Replacing a boiler always triggers a Building Regulations notification because Part G (sanitation/hot water) and Part L (energy efficiency) apply.

This split is the source of much of the public confusion. The page you are reading concerns the Building Regulations side of the equation. For the planning-permission side — including what triggers a full planning application in an English householder context — see our guide on householder planning permission for a garden office.

How to get a Building Regulations Completion Certificate for a boiler

The standard route is via the Competent Person Scheme. A gas engineer registered with a government-approved Competent Person Scheme (such as Gas Safe Register, OFTEC for oil, or HETAS for solid fuel) can self-certify the work and notify Building Control on your behalf. The certification is then recorded centrally.

In England and Wales, the relevant Competent Person Schemes for boiler installation include:

  • Gas Safe Register for natural gas and LPG boilers.
  • OFTEC for oil-fired boilers.
  • HETAS for solid-fuel boilers.

When your installer is registered with one of these schemes, the process is automatic: the engineer submits a Building Regulations notification within 30 days of completing the work, and a Completion Certificate is issued by the relevant scheme operator. You should receive a copy directly.

If your installer is not registered with a Competent Person Scheme, you (or the installer) must give Building Control at least 48 hours’ notice before work starts, by submitting a Building Notice to the local authority. The Building Control body then inspects the work in progress and, on satisfactory completion, issues a Completion Certificate. For information on when Building Regulations approval is required and how to apply, see the GOV.UK building regulations approval service and the Approved Documents collection.

For Scotland, the regime is similar but runs through the local authority’s Building Standards team and uses a different notification form.

Gas Safe Register: a separate scheme

Gas Safe Register is the official gas registration body in Great Britain (replacing the former CORGI registration in 2009). Every engineer who works on gas appliances — including boilers, cookers, and gas fires — must be Gas Safe registered for the type of work they are doing.

A Gas Safe Register certificate confirms:

  • The engineer was qualified for the specific class of work (e.g. natural gas boiler installation).
  • The work was tested for gas tightness and flueing.
  • The appliance was safely commissioned.

A Gas Safe Register certificate is not a substitute for a Building Regulations Completion Certificate. The two documents cover overlapping but distinct compliance requirements. Always retain both.

For the broader PD framework that governs whether you even need a planning application for boiler-related work (e.g. moving a flue, altering an external wall), see our guide on Permitted Development Rights in 2026.

What to do if your installer never issued a certificate

If you cannot find either a Building Regulations Completion Certificate or a Gas Safe Register certificate for your boiler installation, take these steps in order:

  1. Ask the installer. A registered engineer must be able to issue duplicate certificates — both the Building Regulations notification and the Gas Safe certificate — from their records. Most keep records for at least 10 years.
  2. Check the Building Control records. The local authority’s Building Control department (or the private Approved Inspector you used) keeps a public register of completion certificates. You can request a copy or a confirmation letter.
  3. Check the Competent Person Scheme portal. If your installer was registered with Gas Safe Register, OFTEC, or HETAS, you can search the central register for the job. The Planning Portal building regulations section provides a starting point.
  4. Get a retrospective assessment. If no record exists, an independent Building Control body or a suitably qualified consultant can inspect the existing installation and, if compliant, issue a retrospective Completion Certificate. This costs more than the original process and may require remedial work.
  5. Replace the boiler if necessary. If the existing installation cannot be brought up to current Building Regulations standard (e.g. it predates modern condensing-boiler requirements), the practical solution is often to commission a fresh installation by a registered engineer, which will generate new certificates.

Selling a house: why the certificate matters

When you sell a property, the buyer’s solicitor will usually ask for evidence of Building Regulations compliance for any alteration or replacement that has taken place in the last 10–15 years. A boiler installation typically falls into this category. The buyer’s solicitor will look for either:

  • A Building Regulations Completion Certificate, or
  • A retrospective Compliance Certificate from a current inspection.

If neither exists, the buyer’s solicitor may:

  • Insist on a discounted purchase price to cover the cost of retrospective certification.
  • Insist on the work being inspected before exchange of contracts.
  • In rare cases, withdraw from the transaction.

For an LPA-context walkthrough of how building regulations and planning permission interact when selling a property, our Arun District planning guide describes the kind of enquiries that arise from the seller’s pack. For the Airbnb-specific implication — where a buyer’s solicitor may also scrutinise short-term let history — see our Airbnb and short-term let guide.

Next steps and resources

Editorial note. This article is for guidance only and does not constitute regulated advice. Building Regulations and planning permission are distinct regimes with separate certificate requirements. Always retain both certificates for any boiler installation. For project-specific questions, consult a Building Control inspector or a chartered surveyor registered with RICS.