A completion certificate is the document that formally closes out a building regulations application. It tells the world, and specifically your conveyancer, mortgage lender and insurer, that the finished work was inspected and found to comply with the Building Regulations in force at the time. Without it, that assurance disappears entirely.

Most homeowners only discover they need one when they try to sell. Solicitors routinely raise a requisition if building work was carried out without evidence of sign-off, and buyers’ lenders can refuse to proceed. Understanding what a completion certificate is, when you need it and what to do if one is missing can save you serious delay and expense.

What is a completion certificate?

When you notify building control of work that requires regulation approval, an extension, loft conversion, new staircase, electrical rewiring, reroofing, or structural alteration, among others, you are opening a building regulations application. An inspector from either your local authority building control (LABC) or a private registered building control approver (RBCA, the name given to approved inspectors on 6 April 2024 under the Building Safety Act 2022) then inspects the work.1 Visits are typically made at key stages such as the foundations, damp-proof course, structural frame, roof structure and insulation.

Once the work reaches practical completion, you request a final inspection. If the inspector is satisfied, they issue a completion certificate; on a full plans application this usually comes within 8 weeks of the work being completed.2 In England and Wales, LABC certificates are issued under Regulation 17 of the Building Regulations 2010.3 Registered building control approvers issue the equivalent, a final certificate, under their own regulations, the Building (Registered Building Control Approvers etc.) (England) Regulations 2024.4

In Scotland it works the other way round: the person responsible for the work submits a completion certificate to the local authority verifier under section 17 of the Building (Scotland) Act 2003.5 In Northern Ireland the district council issues a completion certificate under regulation 14 of the Building Regulations (Northern Ireland) 2012.6

When do you need one?

You need a completion certificate for any notifiable building work, which broadly covers:

  • Structural alterations (removing load-bearing walls, opening up floor joists, new lintels)
  • Extensions and outbuildings over certain thresholds
  • Loft, garage or basement conversions
  • New bathrooms or kitchens involving drainage
  • Replacement of heating systems, including boiler swaps and heat pump installations, usually self-certified by a registered installer rather than inspected by building control7
  • Electrical installation work that is notifiable under Part P8
  • New staircases and balustrades
  • Underpinning9

Where an installer registered with a competent person scheme does the work, building control does not inspect it: the installer must give you a certificate that the work complies within 30 days of finishing and notify the council, and that certificate stands in for a completion certificate.10

Permitted development work that is also notifiable, a rear extension, for instance, still requires building regulations sign-off even though no planning permission was needed.11

Why it matters for property transactions

Conveyancers check for completion certificates as standard because a certificate is evidence, though not conclusive evidence, that the work met the Building Regulations.3 A mortgage lender will usually want documented evidence of regulatory compliance rather than a structural surveyor’s opinion alone. If you cannot produce a completion certificate, a buyer’s solicitor will typically ask for one of three things: a regularisation certificate from the local authority, a copy of the original approval and inspection records, or indemnity insurance.

Indemnity insurance covers the buyer and their lender against the risk of the local authority issuing an enforcement notice, but it is not the same as a completion certificate and should be a last resort rather than a standard workaround.

Costs and timescales

RouteTypical costTimescale
New building regulations application (notifiable work underway)£200–£1,200 depending on project sizeWeeks to months
Regularisation certificate (retrospective, LABC only)Council fee plus a surcharge: about £440 for minor work to £1,200+ for an extension4–12 weeks
Indemnity insurance (instead of regularisation)Typically £20–£300 one-off premium; more for larger works or valuable homesMinutes to several days
Registered building control approver (RBCA) final certificateIncluded in the approver’s fee, which is quoted per jobSubject to inspection

Local authority fees vary: a London borough will charge more than a rural district council. Hillingdon, for example, charges £440 to regularise a chimney breast removal or a simple structural opening and £1,210 for an extension under 40 m².12 Its regularisation charges include a 30% surcharge on the normal fee.12 The regularisation route requires the building owner to expose sufficient areas of the work for inspection, reopening plastered walls or lifting floors, which adds contractor costs on top of the council fee.

What to do if a completion certificate is missing

Step 1, Search your local authority records. Building control records are not always indexed under the current owner’s name. Call the LABC and provide the property address and approximate date of the works. Many councils have digitised records going back to the 1980s; others can search paper files. Councils may charge for a search or for a copy of a certificate: Lambeth, for example, charges £144 for each copy.13

Step 2, Check with the original registered building control approver. If an RBCA or, before April 2024, an approved inspector was used, they must have given their final certificate to the local authority.14 The RBCA may also hold copies; the sector has seen consolidation, but records often transfer to successor firms.

Step 3, Apply for a regularisation certificate. This is available only from LABC (not private RBCAs) and only for work carried out on or after 11 November 1985.15 You send a description of the work, a plan of it and a plan of any further work needed to meet the regulations that applied when it was done, and the council can require you to lay the work open for inspection.15 On satisfactory inspection, the authority issues a regularisation certificate, which conveyancers generally accept in place of a completion certificate.

Step 4, Consider indemnity insurance. If the work is old (pre-1985, or more than 10 years old, past the time limit for a council enforcement notice under section 36 of the Building Act 1984), if opening up is impractical, or if the transaction timeline is tight, indemnity insurance is often the fastest resolution.16 Premiums are a single payment, typically £20–£300, and who pays is open to negotiation.17 Note that contacting the local authority after deciding to go down the insurance route can invalidate the policy, seek legal advice first.

Selling a property with missing completion certificates

Disclose the issue to your solicitor at the outset. They will assess which route is most appropriate depending on the age and nature of the works, the buyer’s lender requirements and the urgency of exchange. Trying to hide a missing certificate is not only wrong but legally risky: a buyer who contracts on the strength of a misrepresentation can claim damages and may be able to rescind the contract.18

Building Safety Act 2022 changes

The Building Safety Act 2022 reformed building control in England. From April 2024, private approved inspectors became Registered Building Control Approvers regulated by the Building Safety Regulator.1 Higher-risk buildings (HRBs: at least 18 m high or at least 7 storeys, with at least 2 residential units) go through a more stringent Gateway process, in which the Building Safety Regulator itself approves the work and issues the completion certificate only when satisfied that the work meets the building regulations.19 For most domestic renovation work, the practical impact is limited, but it is worth noting that the regulatory landscape has shifted.

Practical tips

  • Request your completion certificate the moment the inspector approves the final inspection. Builders sometimes move on and final paperwork is never requested.
  • Keep all building regulations documentation together with your title deeds or in a dedicated home file, a solicitor will thank you, and you will thank yourself at sale time.
  • If you are buying a property with recently completed extensions or conversions, always ask your solicitor to requisition the completion certificate rather than accepting the seller’s assurances.
  • For work that genuinely did not require building regulations approval (most like-for-like repairs, painting and decorating, fitting kitchens without drainage changes), there is no completion certificate to obtain, a letter from a suitably qualified building professional confirming the exemption can be helpful instead.
References (19)

Figures in this note were checked against the sources below on 2 October 2026. Superscript numbers in the text point to them. Every source the site cites, by topic.

  1. 1technicalvery strongPlanning Portal, guidance.RN-WV45MHPlanning Portal guidance on private building control. It explains that registered building control approvers replaced approved inspectors, with registration required by 6 April 2024.
  2. 2technicalvery strongGOV.UK, a government page.RN-JYRZYTHow to get building regulations approval: the choice between a full plans application and a building notice, using a competent person scheme instead where the work qualifies, and the determination and appeal routes if approval is refused. This is the page that decides which route a job takes, and the route decides both the fee and how much can go wrong on site before anyone checks.
  3. 3technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-0BAHFURegulation 17(1) requires the relevant authority to give a completion certificate in all cases where, after taking all reasonable steps, it is satisfied that the relevant provisions have been complied with following completion of the building work. Regulation 17(2) sets the specified period at eight weeks starting from the date the authority receives the regulation 16(4) completion notice, or the equivalent notice under regulation 22A(1) of the Building (Registered Building Control Approvers etc.) (England) Regulations 2024. The relevant provisions checked are listed at 17(2A) and include regulation 25A high-efficiency alternative systems, regulation 26 target CO2 emission rates, regulation 26A target fabric energy efficiency, regulation 26C target primary energy rates, regulation 36 water efficiency, regulation 38 fire safety information, Schedule 1, and regulation 7A of the Energy Performance of Buildings (England and Wales) Regulations 2012. Critically, regulation 17(4) states the certificate is evidence but not conclusive evidence of compliance, and 17(5) requires the certificate itself to say so. This version applies to England only.
  4. 4technicalvery strongThe National Archives (legislation.gov.uk), guidance.RN-WDR7CVThe 2024 regulations under which registered building control approvers work in England: initial notices, amendment notices, consultation, plans certificates and final certificates.
  5. 5technicalvery strongThe National Archives (legislation.gov.uk), guidance.RN-PLCHI4The Scottish statutory provision on completion certificates. It puts the duty on the relevant person to submit the certificate to the verifier after warrant work is finished.
  6. 6technicalvery strongThe National Archives (legislation.gov.uk), guidance.RN-UQQM60The Northern Ireland regulation on completion certificates. It requires the district council to issue a completion certificate once satisfied the relevant requirements are met.
  7. 7technicalvery strongMinistry of Housing, Communities and Local Government.RN-SAMO3MThe official list of competent person schemes whose members can self-certify certain building work instead of getting building regulations approval, published 4 April 2013 and last updated 12 March 2018. Named schemes with contact numbers include ATTMA, APHC, Assure Certification, Blue Flame Certification, the British Board of Agrement, BESCA, Capita Gas Registration and Ancillary Services trading as Gas Safe Register, CIGA, Certass, Certsure LLP trading as NICEIC, the Elmhurst Airtightness Scheme, Fensa Limited, HETAS Limited, NAPIT Registration Limited, the National Federation of Roofing Contractors trading as CompetentRoofer, and OFTEC. Two footnotes matter: the Gas Safe Register is not technically a competent person scheme although in practice its installers carry the same building regulations responsibilities, and Benchmark Certification Limited ceased to operate as a competent person scheme on 10 February 2017, becoming part of NAPIT Registration Limited that day. Installers joining an electrical scheme are added to the single electrical competent person register.
  8. 8technicalvery strongMinistry of Housing, Communities and Local Government.RN-JYJ3I5The document that decides what electrical work a homeowner may legally do themselves, and the exact list of notifiable jobs. Regulation 12(6A), reproduced at paragraph 2.5, makes only three things notifiable: the installation of a new circuit, the replacement of a consumer unit, and any addition or alteration to existing circuits in a special location. Regulation 12(9) defines special location as, in a room containing a bath or shower, the zone extending vertically from finished floor level to 2.25 metres (or the shower head position if higher) and horizontally 600mm from the edge of the bath tub or shower tray. Paragraph 2.7 states that all other electrical installation work is not notifiable, namely additions and alterations to existing installations outside special locations, and replacements, repairs and maintenance anywhere. Paragraph 2.8 gives worked examples: a built-in cooker is not notifiable unless a new cooker circuit is needed, and connecting an electric gate or garage door to an existing isolator is not notifiable but running a new circuit from the consumer unit to that isolator is. Paragraph 2.2 confirms Part P reaches outdoor work including fixed garden lighting, pond pumps and outbuildings such as sheds, detached garages and domestic greenhouses. Notifiable work must be certified by self-certification by a registered competent person, third-party certification, or a building control body (paragraph 3.1), with the compliance certificate issued within 30 days (paragraph 3.4). Note that Approved Document P is a source of guidance rather than a ban: non-notifiable work still has to comply with BS 7671.
  9. 9technicalvery strongThe National Archives, legislation.RN-ZCMRHVRegulation 3 of the Building Regulations 2010, the meaning of building work. Lists what counts: erecting or extending a building, providing or extending a controlled service or fitting, material alteration, work required by a material change of use, and inserting insulation into a cavity wall. If a job is not on this list it is not building work, so this is the first place to check whether approval is needed at all.
  10. 10technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-TISY8ORegulation 20 of the Building Regulations 2010 is the legal basis for every competent person certificate and, importantly, the deadline attached to it. Paragraph (1) applies the regulation where the building work consists only of work of a type described in column 1 of the Table in Schedule 3 carried out by a person described in column 2. Paragraph (2): the building control authority is authorised to accept, as evidence that the requirements of regulations 4 and 7 have been satisfied, a certificate to that effect from the person carrying out the work. Paragraph (3): within 30 days of completing the work that person must give the occupier a copy of the certificate and either notify the building control authority or send it the certificate. Paragraph (3A) requires the authority to keep a retrievable copy. Paragraph (5) is the sting: such a certificate is evidence, but not conclusive evidence, that the requirements have been complied with. If an installer has not produced the certificate within 30 days, chase it before final payment.
  11. 11technicalvery strongPlanning Portal, guidance.RN-4IXS1PPlanning Portal guidance on extensions. It notes an extension can be permitted development yet still needs approval under the Building Regulations, which are a separate regime.
  12. 12coststrong locallyLondon Borough of Hillingdon.RN-XNWC03A price, true at 2026-09. Hillingdon's 2026-27 building control fee schedule lists a regularisation charge for each type of domestic work: £1,210 for an extension under 40 m² and £440 for minor works such as chimney breast removal or a simple structural opening.
  13. 13technicalstrong locallyLambeth Council, guidance.RN-4B0TDEA London borough's building control page on completion certificates. It shows councils can charge for copies of past certificates, here £144 including VAT per copy.
  14. 14technicalvery strongThe National Archives (legislation.gov.uk), guidance.RN-HSA990Section 51 requires a registered building control approver, once satisfied the work is complete, to give the local authority a final certificate for work under its initial notice.
  15. 15technicalvery strongThe National Archives, legislation.RN-4MV2ZGRegulation 18 of the Building Regulations 2010, unauthorised building work. Where work was carried out on or after 11 November 1985 without approval, the owner may apply in writing for a regularisation certificate. This is the route out of discovering at sale that an extension or loft conversion was never signed off, and the date in it is why anything older is outside the process.
  16. 16technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-NKK4KZSection 36(1) lets the building control authority, without prejudice to prosecuting for a fine, serve notice on the owner requiring work that contravenes building regulations to be pulled down or removed, or at the owner's election altered so as to comply. Section 36(2) applies the same power where work was executed without an application for building control approval, despite refusal of one, or otherwise than in accordance with the requirements of a granted application. Section 36(3) gives the owner 28 days, or longer if the appropriate court or tribunal allows, before the authority may carry out the work itself and recover the reasonable expenses. Section 36(4) is the key protection: a section 36 notice may not be given after 10 years from the date the work was completed. Sections 36(5) and 36(5A) bar a section 36 notice where a building control approval application for work that is not higher-risk building work was granted and the work was executed in accordance with the approved plans and any requirement imposed.
  17. 17costfairHomeOwners Alliance.RN-FTR5SQA price, true at 2026-09. HomeOwners Alliance guide for owners whose property lacks a building regulations certificate. It gives the typical cost of a building regulations indemnity policy as £20 to £300.
  18. 18technicalvery strongThe National Archives (legislation.gov.uk), guidance.RN-3VD46BSection 2 of the Misrepresentation Act 1967 (England and Wales): a party induced into a contract by a misrepresentation can recover damages, and the court's powers where rescission is claimed.
  19. 19technicalvery strongBuilding Safety Regulator, guidance.RN-0VUFHQGovernment guidance on building control for higher-risk buildings. It defines HRBs as at least 7 storeys or 18 m with at least 2 residential units and says BSR issues their completion certificates.

  1. Registered building control approver services, Planning Portal, accessed 29 September 2026. planningportal.co.uk

  2. Building regulations approval: how to apply, GOV.UK, accessed 2 October 2026. gov.uk

  3. The Building Regulations 2010, regulation 17: Completion certificates, The National Archives (legislation.gov.uk), accessed 29 September 2026. legislation.gov.uk

  4. The Building (Registered Building Control Approvers etc.) (England) Regulations 2024, legislation.gov.uk, accessed 29 September 2026. legislation.gov.uk

  5. Building (Scotland) Act 2003, section 17: Completion certificates, The National Archives (legislation.gov.uk), accessed 29 September 2026. legislation.gov.uk

  6. The Building Regulations (Northern Ireland) 2012, regulation 14: Completion certificates, The National Archives (legislation.gov.uk), accessed 29 September 2026. legislation.gov.uk

  7. Competent person scheme: current schemes and how schemes are authorised, Ministry of Housing, Communities and Local Government, accessed 29 September 2026. gov.uk

  8. Approved Document P, Electrical safety: Dwellings, 2013 edition incorporating 2010 and 2013 amendments, Ministry of Housing, Communities and Local Government, accessed 14 September 2026. assets.publishing.service.gov.uk

  9. The Building Regulations 2010, regulation 3: Meaning of building work, The National Archives (legislation.gov.uk), accessed 29 September 2026. legislation.gov.uk

  10. The Building Regulations 2010, regulation 20: Provisions applicable to self-certification schemes, The National Archives (legislation.gov.uk), accessed 29 September 2026. legislation.gov.uk

  11. Planning permission and building regulations: extensions, Planning Portal, accessed 29 September 2026. planningportal.co.uk

  12. Building Control Fees 2026-27, London Borough of Hillingdon, accessed 30 September 2026. Priced at 2026-09 and left there. pre.hillingdon.gov.uk

  13. Completion certificates, Lambeth Council, accessed 29 September 2026. lambeth.gov.uk

  14. Building Act 1984, section 51: Final certificates, The National Archives (legislation.gov.uk), accessed 29 September 2026. legislation.gov.uk

  15. The Building Regulations 2010, regulation 18: Unauthorised building work, The National Archives (legislation.gov.uk), accessed 29 September 2026. legislation.gov.uk

  16. Building Act 1984, section 36: Removal or alteration of offending work, legislation.gov.uk, accessed 29 September 2026. legislation.gov.uk

  17. No Building Regulations Certificate? What Can You Do?, HomeOwners Alliance, accessed 2 October 2026. Priced at 2026-09 and left there. hoa.org.uk

  18. Misrepresentation Act 1967, section 2: Damages for misrepresentation, legislation.gov.uk, accessed 2 October 2026. legislation.gov.uk

  19. Building control approval for higher-risk buildings, Building Safety Regulator, accessed 29 September 2026. gov.uk