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Building Regulations Completion Certificate: A 2026 Guide for UK Homeowners

Bhavesh Ramburn

What is a Building Regulations Completion Certificate?

A Building Regulations Completion Certificate (often called a Completion Certificate or Compliance Certificate) is a document issued by a Building Control body confirming that building work has been completed in accordance with the Building Regulations (SI 2010/2214) made under the Building Act 1984.

The Completion Certificate is the formal proof that the work was inspected by a Building Control inspector at the key construction stages and that the completed work met the relevant Approved Documents (Parts A–S of the Building Regulations).

There are two slightly different flavours of the document:

  • Completion Certificate — issued by the local authority Building Control team when it has carried out the inspection function.
  • Final Certificate — issued by an Approved Inspector when it has carried out the inspection function. See our Building Control Initial Notice guide for the Approved Inspector transfer mechanism.

Both documents have the same legal status for the purposes of the Building Regulations. The Completion Certificate is the more common term; the Approved Inspector’s document is technically a Final Certificate but is often referred to as a Completion Certificate in practice.

For the broader context on building regulations and the regime that produces these certificates, see our Building Regulations UK guide.

When you receive one

A Completion Certificate is issued by the Building Control body on satisfactory completion of the work. The process is:

  1. The application (Full Plans or Building Notice) is approved or acknowledged.
  2. Work proceeds, with inspections at key stages (excavation, damp-proof course, oversite, pre-plaster, drain test, completion).
  3. The Building Control inspector visits at the completion stage and confirms that the work is satisfactory.
  4. The Building Control body issues the Completion Certificate, typically within a few weeks of the final inspection.

For a full list of inspection stages, see our Building Control Application guide.

You should receive the Completion Certificate directly from the Building Control body (or Approved Inspector). Retain the original document for the lifetime of the building — you will need it when you sell the property.

The Completion Certificate and selling a house

The Completion Certificate is one of the standard documents requested by a buyer’s solicitor during the conveyancing process. The buyer’s solicitor will typically ask for evidence of Building Regulations compliance for any building work carried out at the property in the last 10–15 years.

If a Completion Certificate exists, the buyer’s solicitor will record it on the title and the sale can proceed.

If a Completion Certificate does not exist, the buyer’s solicitor may:

  • Insist on a discounted purchase price to cover the cost of retrospective certification (a regularisation application, typically 150% of the standard fee).
  • Insist on the work being inspected before exchange of contracts, with a contingency for remedial work if the inspection finds non-compliance.
  • Apply for indemnity insurance as an alternative to retrospective certification (cheaper but does not actually make the work compliant).
  • In rare cases, withdraw from the transaction if the buyer’s mortgage lender refuses to lend against a property with no evidence of Building Regulations compliance.

For work that is more than 10 years old, the 10-year rule under section 124 of the Building Act 1984 may apply — the local authority can no longer take enforcement action, even if no Completion Certificate was ever issued. For more on this, see our Building Regulations 10-Year Rule guide.

What to do if you can’t find yours

If you cannot find the Completion Certificate for work that was carried out at your property, the most likely explanations are:

  • The work was never the subject of a Building Regulations application. This is common for older properties (pre-1990s) and for work carried out by an installer who did not make a separate application.
  • The Completion Certificate was issued but is lost. The original may have been filed away and lost during a previous ownership or refurbishment.
  • The work was carried out by a Competent Person Scheme member. In this case, the certification is recorded centrally (e.g. by Gas Safe Register, OFTEC, NICEIC) but you may not have received a paper certificate. See our boiler installation certificate guide for a specific example.

For each situation, the response is different:

  1. No application was made. The work is technically non-compliant. You can apply for a regularisation certificate from the local authority (see below), or rely on the 10-year rule if the work is old enough.
  2. Lost certificate. Apply to the Building Control body for a duplicate or a copy from their records.
  3. Competent Person Scheme work. Contact the relevant scheme operator (e.g. Gas Safe Register, NICEIC) to confirm whether the work was self-certified.

How to get a copy of a Completion Certificate

If you need a copy of an existing Completion Certificate, the local authority’s Building Control team is the first port of call. Most Building Control teams keep records going back at least 10 years, and many have searchable online registers.

The typical process is:

  1. Identify the local authority that issued the original certificate. For work at a single property, this is the LPA covering the address.
  2. Contact the Building Control team by phone, email, or online form. Provide the property address and (if known) the application reference number, the year of the work, and the name of the original applicant.
  3. Pay the duplication fee. Most Building Control bodies charge a small fee (typically £30–£80) for retrieving and copying records.
  4. Receive the duplicate. The Building Control body will either provide a paper copy or a digital PDF.

If the work was carried out by an Approved Inspector, the Final Certificate is held by the Approved Inspector’s records — contact the firm that carried out the work (or the Approved Inspector named on the Initial Notice).

For records of work carried out by a Competent Person Scheme member, contact the scheme operator. For example, Gas Safe Register maintains a central register of gas work self-certifications, and NICEIC maintains a similar register for electrical work.

Regularisation certificates: when work was done without one

A regularisation certificate is a retrospective Completion Certificate issued by the local authority where the original work was carried out without a Building Regulations application. The application process is similar to a normal application, but with two important differences:

  1. The application is made after the work is complete — there is no plans check before construction. The local authority inspects the work as it stands.
  2. The fee is higher — typically 150% of the standard fee that would have applied for a new application.

If the regularisation inspection finds that the work is non-compliant, the local authority can require the owner to put the work right before issuing the regularisation certificate. In extreme cases, the local authority can require the owner to remove the non-compliant work and rebuild it to current standards — at the owner’s expense.

The regularisation application is a useful tool where work was done without a Building Regulations application and you need to bring it into compliance — typically because you are selling the property and the buyer’s solicitor is asking for evidence.

For an LPA-specific worked example of building control processes, see our Bradford building control guide.

The Final Certificate from an Approved Inspector

When an Approved Inspector has carried out the building control function (via the Initial Notice mechanism under section 47 of the Building Act 1984), the document they issue on satisfactory completion is technically called a Final Certificate, not a Completion Certificate.

The Final Certificate has the same legal effect as a Completion Certificate for the purposes of proving Building Regulations compliance. It is referenced in the Initial Notice documentation and is held by the Approved Inspector’s records.

If you need a copy of a Final Certificate, contact the Approved Inspector that issued it. The Construction Industry Council Approved Inspectors Register (CICAIR) can help locate the Approved Inspector if the firm has since closed.

For the broader context on Approved Inspectors and the Initial Notice process, see our Building Control Initial Notice guide.

Next steps and resources

Editorial note. This article is for guidance only and does not constitute regulated advice. Completion Certificate procedures vary slightly between local authorities. For project-specific questions, contact your local Building Control team or a chartered surveyor registered with RICS.