Building control inspections are the practical mechanism by which England’s Building Regulations are enforced on site. They are not optional and not merely bureaucratic box-ticking, they exist because failures in structural, drainage, fire, and thermal standards are expensive or catastrophic to correct after walls are plastered and floors are laid. Understanding when inspections happen, who carries them out, and what they cover helps you manage your build without delays or enforcement notices.

Who Carries Out Inspections?

There are two routes to building control in England and Wales:

Local Authority Building Control (LABC): Provided by your local council. Fees vary by authority and project type.1 Applications are made directly to the council, and their surveyors carry out site inspections. They are a public body with statutory powers.

Registered Building Control Approver (RBCA, formerly Approved Inspector): A private body registered with the Building Safety Regulator.2 They provide the same statutory approval function but operate commercially. NHBC, for example, is a registered building control approver.3 Since the Building Safety Act 2022, the terminology has changed from “Approved Inspector” to “Registered Building Control Approver,” but the function is the same.

For most domestic work, either route is valid. Cost and turnaround time for decisions vary, a private RBCA is sometimes faster on complex projects, but LABC is the default for most householders.

Notifiable vs. Exempt Work

Not all work needs Building Regs approval. Work that is not building work at all, or is exempt under Schedule 2 of the Building Regulations 2010, includes:

  • Most repairs and like-for-like replacements (subject to exceptions)
  • Small detached single-storey outbuildings with a floor area of no more than 30 m² and no sleeping accommodation, sited at least 1 m from the boundary or built substantially of non-combustible material4
  • Porches added at ground level with a floor area of no more than 30 m², provided any glazing meets the safety glazing requirements of Part K4

Notifiable work includes: extensions, loft conversions, garage conversions, structural alterations, new drainage, rewiring (unless done under a Part P competent person scheme), new boiler or central heating system, and replacement windows (unless installed by a FENSA/CERTASS registered installer).56

If in doubt, contact your LABC before starting work, checking is usually free, and proceeding without approval when required is a criminal offence.7

Application Types

Building Notice (BN): A simpler, faster application. You submit basic information and can start work 2 days after the notice is given.1 No plans are formally approved in advance, the inspector visits as work progresses and checks compliance on site. Works well for smaller projects where the builder knows the regs. Risk: if the inspector identifies a non-compliant detail, you may have to alter or demolish work already completed.

Full Plans (FP): You submit detailed drawings and specifications before starting. The council or approver checks the plans and issues an approval notice (the local authority must give its decision within 5 weeks, or a longer period you agree in writing).8 Work can then proceed with confidence that the design is regs-compliant, inspections verify it is being built as designed. Better for complex projects, loft conversions, extensions, or where mortgage lenders require evidence of approved plans.

Regularisation: Applied for retrospectively when work has already been completed without Building Regs approval.9 The inspector may require invasive opening-up to verify hidden work (e.g., foundations, drainage). Fees are higher: Solihull, for example, charges £710 to regularise a small extension, against £660 for a building notice.10 A regularisation certificate (rather than a completion certificate) is issued.

The Inspection Stages

The number and type of inspections varies with project type. For a typical domestic extension or loft conversion, expect the following staged inspections. The stages are not fixed in law: once you have given notice of the start, the local authority can tell you in writing which stages it intends to inspect, based on its assessment of risk, and when to notify it.11 The builder must then notify Building Control at each of those stages, before the work is covered up.

StageWhat the inspector checksNotice required
CommencementNotice of start; some surveyors also check the site set-outAt least 2 days before starting
Excavation / foundationsDepth and width of strip/raft; soil conditions; any contaminationBefore concrete is poured
Concrete pourConcrete specification; foundation thickness; DPC levelDuring pour or immediately after
Damp-proof course (DPC)DPC height above external ground level (min 150 mm); cavity tray detailsBefore brickwork above DPC is laid
Structural frame (oversite)Steel beams, padstones, bearing details as designedBefore encasing in masonry or boarding
DrainageFall, gradient, pipe joints, inspection chamber positions, surcharge testBefore backfilling trenches
Floor constructionInsulation, vapour control layer; screed depthBefore screed is poured
Roof structureTrussed rafters or cut roof; bracing; water-tightnessBefore tiling or felting
Insulation / airtightnessWall, roof, and floor insulation values; continuity; airtightness measuresBefore covering with boards or plaster
CompletionFull walkthrough; fire doors; ventilation; electrics (Electrical Installation Certificate); structural completionWithin 5 days of completion

The 150 mm DPC minimum in the table comes from Approved Document C: in an external wall the damp-proof course should be at least 150 mm above the level of the adjoining ground.12 For a loft conversion, additional inspections cover the new floor structure, fire-rated ceiling, escape window, and staircase rise-and-going compliance. Where new below-ground drainage is laid, expect the surveyor to want it tested for watertightness, by an air test or a water test, before the trench is backfilled.13

What Happens If You Miss a Stage?

If you cover up work without notifying Building Control and they have not inspected it, the inspector has the right to require you to open up the work at your own cost so it can be inspected.11 On a simple foundation, this might mean breaking up concrete; on finished drainage, it means digging up a trench. The cost can run to thousands of pounds.

In practice, experienced surveyors will often accept photographic evidence (time-stamped, showing the work clearly) for stages where opening up is not possible, but this is at their discretion, not your right. Always notify in advance.

Completion Certificate

At the end of the project, once the inspector is satisfied that all work complies, Building Control issues a Completion Certificate.14 This is an important legal document, retain it with your property’s records.

Without a completion certificate:

  • Selling is harder: buyers’ solicitors ask for the certificate, and the usual fixes, a retrospective regularisation certificate or indemnity insurance, cost time and money5
  • Mortgage lenders and conveyancers will flag the gap in records
  • Your home insurer may have grounds to contest claims arising from the works
  • If the works prove unsafe, you have no independent record that they were checked

Obtaining the completion certificate is a stage many self-managers neglect. Budget for a final inspection visit and, if required, submit any completion documents (Gas Safe certificate, Electrical Installation Certificate, window FENSA certs) that the inspector needs before issuing it.

Competent Person Schemes

For certain work, specifically electrical, gas, glazing, and some heating work, registered tradespeople can self-certify compliance without a Building Regs application.15 Schemes include:

SchemeCovers
FENSA / CERTASSWindow and door replacement
Gas Safe RegisterGas appliances and pipework
NICEIC (Certsure) / NAPIT / BESCAElectrical work (Part P)
HETASSolid fuel heating appliances

The government keeps the current list of authorised schemes: for electrical installations in homes it names BESCA, Blue Flame Certification, Certsure (NICEIC), NAPIT and OFTEC.16 MCS, often listed alongside these, is not one of them: it certifies microgeneration installers for grants such as the Boiler Upgrade Scheme, and a heat pump installer self-certifies the Building Regulations side through a competent person scheme. Work done under these schemes needs no separate Building Regs application, and within 30 days of finishing the installer must give you a certificate and notify the local authority (in practice the scheme usually does this for them).17 Keep all certificates, they form part of your property’s compliance record.

References (17)

Figures in this note were checked against the sources below on 30 September 2026. Superscript numbers in the text point to them. Every source the site cites, by topic.

  1. 1technicalvery 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.
  2. 2technicalvery strongBuilding Safety Regulator (GOV.UK), a government page.RN-KU9CUNBuilding Safety Regulator guidance on registering as a building control approver. Every private sector business doing building control work in England and Wales under the Building Act 1984 as amended must now register with the BSR. This is the rule that replaced the approved inspector regime, and it is why the register is the thing to check before appointing a private inspector.
  3. 3technicalstrongNHBC, guidance.RN-RE9G94NHBC's page for its building control service, stating that NHBC is a Registered Building Control Approver under the Building Safety Regulator's regime and working on residential and commercial schemes.
  4. 4technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-Y7MVZKClass 7 is the conservatory and porch exemption every extension note leans on: the erection at ground level of an extension consisting of a conservatory, porch, covered yard or covered way, or a carport open on at least two sides, is exempt from the building regulations where the floor area does not exceed 30 square metres. Where a conservatory or porch is wholly or partly glazed, the glazing must still satisfy Part K4 and K5.1 to K5.4 and Part N of Schedule 1. Class 6 exempts small detached buildings up to 30 square metres single storey and up to 15 square metres otherwise, which is the garden room threshold.
  5. 5technicalvery strongGOV.UK, guidance.RN-81EIUNThe government's own list of alterations that need building regulations approval, and the page to cite when a reader asks whether a bathroom or kitchen refit is notifiable. Works listed as needing approval include installing a bathroom that will involve plumbing, changing electrics near a bath or shower, replacing a fuse box and connected electrics, replacing windows and doors, replacing roof coverings, installing or replacing a heating system, adding radiators to an existing heating system, and installing fixed air conditioning. Emergency repairs to a boiler or heating system do not need approval in advance, though specific rules then apply. Approval may be obtained from a local authority building control department, a private registered building control approver, or, for higher-risk residential buildings, the Building Safety Regulator. The page states the practical consequence bluntly: without approval you will not have the certificates of compliance you may need when you want to sell your home. Note that a like-for-like bathroom refit with no new plumbing, no drainage change and no work in the electrical zones is not on the list.
  6. 6technicalvery 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.
  7. 7technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-0GJHBJSection 35 of the Building Act 1984, as amended by the Building Safety Act 2022, makes contravening building regulations a criminal offence and sharply increased the punishment. A person who contravenes a provision of building regulations, or a requirement imposed by virtue of such a provision, commits an offence. Under subsection (4) a person guilty of the offence is liable on summary conviction to imprisonment for a term not exceeding the maximum summary term for either-way offences, or to a fine, or both; and on conviction on indictment to imprisonment for up to two years, or a fine, or both. After conviction, continued default attracts a further fine on summary conviction not exceeding level 1 on the standard scale for each day the default continues. Building regulations may exempt prescribed provisions from creating an offence or provide defences. Note the separate two-year enforcement time limit in section 35A and the section 36 power to require removal or alteration of offending work.
  8. 8technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-A6L0BBRegulation 14A of the Building Regulations 2010, determination of applications for building control approval with full plans. The authority must grant approval unless the application fails regulation 14's requirements or the work would contravene the regulations. The provision that turns a full plans application into a decision the authority has to justify, which is the practical difference between full plans and a building notice.
  9. 9technicalvery 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.
  10. 10coststrong locallySolihull Metropolitan Borough Council.RN-XSQV70A price, true at 2026-09. Solihull Metropolitan Borough Council's published price for the item the cost register files as "building Regulations application fee, plan charge, England", which is the figure a cost footnote on this page points at.
  11. 11technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-6CCBA1Regulation 16(1) bars starting building work until notice of intention to start has been given to the relevant authority and at least two days have elapsed since the end of the day the notice was given. Regulation 16(3) lets the authority serve written notice requiring notification when a specified stage is reached, and may set a period before or after the work within which to notify and a period during which the work must not be covered up; under 16(3A) and 16(3B) a stage may only be specified if the authority intends to inspect it, based on its assessment of the risk of a breach. Regulation 16(3C) requires notice that work has commenced within five days of commencement, with a rejection notice possible within four weeks (16(3E)), deemed commencement if no rejection is given (16(3F)), and an appeal to the First-tier Tribunal within 21 relevant days (16(3H)) on grounds of error of fact, error of law, unreasonableness or failure to follow procedure. Regulation 16(4) requires notice within five days of completion.
  12. 12technicalvery strongMinistry of Housing, Communities and Local Government.RN-NPO8FJThe statutory figures behind a damp diagnosis, and the numbers to quote when a note explains why ground levels or a bridged damp proof course cause rising damp. Paragraph 5.2 requires that in an external wall the damp-proof course should be at least 150mm above the level of the adjoining ground (Diagram 8) unless part of the building protects the wall, and that in an external cavity wall the cavity should be taken down at least 225mm below the level of the lowest damp-proof course, or a damp-proof tray provided (Diagram 9a). For suspended timber ground floors it requires a ventilated air space of at least 75mm from the ground covering to the underside of any wall-plates and at least 150mm to the underside of the suspended timber floor or insulation, with ventilation openings on two opposing external walls of not less than 1,500mm2 per metre run of external wall or 500mm2 per square metre of floor area, whichever is greater; for suspended concrete floors the clear ventilated space is at least 150mm with the same opening sizes. Section 2.39 onwards covers radon, referring to BRE Report BR 211 for protective measures. The 2013 edition was published on 3 September 2013 with changes in effect from 1 October 2013.
  13. 13technicalvery strongMinistry of Housing, Communities and Local Government.RN-SM6TRWThe statutory source for soakaway design and the discharge hierarchy every garden drainage note should state. Requirement H3(3) lists the order of priority for rainwater discharge: (a) an adequate soakaway or other adequate infiltration system, or where not reasonably practicable (b) a watercourse, or where not reasonably practicable (c) a sewer. Paragraph 3.25 bars infiltration devices within 5 metres of a building or road, in ground where the water table reaches the bottom of the device at any time of year, too close to other drainage fields or soakaways, or where contamination could pollute groundwater. Paragraph 3.26: soakaways serving less than 100 square metres are generally square or circular pits filled with rubble or lined with dry-jointed masonry or perforated ring units. Paragraph 3.27: design to a return period of once in ten years, and for small soakaways serving 25 square metres or less a design rainfall of 10mm in 5 minutes may be assumed as the worst case. Paragraph 3.28 requires percolation tests to derive the infiltration rate, and paragraph 3.30 sends larger soakaways to BS EN 752-4 or BRE Digest 365 Soakaway design. Paragraphs 2.10 to 2.12 cover pervious paving over a granular storage reservoir and warn against its use where sediment or oil spillage would block the pores. For foul drainage, paragraph 2.33 sets a minimum 75mm internal diameter, or 100mm for a WC, and Table 6 gives minimum gradients of 1 in 40 for 75mm and 100mm at peak flows under 1 litre per second.
  14. 14technicalvery 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.
  15. 15technicalvery strongGOV.UK, guidance.RN-YYKICUGOV.UK guidance explaining that installers registered with a competent person scheme, for example for windows or boilers, self-certify work instead of the owner applying for approval.
  16. 16technicalvery 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.
  17. 17technicalvery 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.

  1. Building regulations approval: How to apply, GOV.UK, accessed 29 September 2026. gov.uk

  2. Register your business as a building control approver, Building Safety Regulator (GOV.UK), accessed 29 September 2026. gov.uk

  3. Building Control Services and Inspection, NHBC, accessed 30 September 2026. nhbc.co.uk

  4. The Building Regulations 2010, Schedule 2: Exempt buildings and work, legislation.gov.uk, accessed 29 September 2026. legislation.gov.uk

  5. Building regulations approval, GOV.UK, accessed 29 September 2026. gov.uk

  6. 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

  7. Building Act 1984, section 35: Offence of contravening building regulations etc, legislation.gov.uk, accessed 29 September 2026. legislation.gov.uk

  8. The Building Regulations 2010, regulation 14A, legislation.gov.uk, accessed 29 September 2026. legislation.gov.uk

  9. The Building Regulations 2010, regulation 18: Unauthorised building work, legislation.gov.uk, accessed 29 September 2026. legislation.gov.uk

  10. Guidance notes on Building Regulation Charges, effective from 1 April 2026, Solihull Metropolitan Borough Council, accessed 30 September 2026. Priced at 2026-09 and left there. solihull.gov.uk

  11. The Building Regulations 2010, regulation 16: Notices in relation to building work, legislation.gov.uk, accessed 29 September 2026. legislation.gov.uk

  12. Approved Document C, Site preparation and resistance to contaminants and moisture, 2004 edition incorporating 2010 and 2013 amendments, HM Government, accessed 30 September 2026. assets.publishing.service.gov.uk

  13. Approved Document H, Drainage and waste disposal, 2015 edition, HM Government (GOV.UK), accessed 29 September 2026. assets.publishing.service.gov.uk

  14. The Building Regulations 2010, regulation 17: Completion certificates, legislation.gov.uk, accessed 29 September 2026. legislation.gov.uk

  15. Building regulations approval: Use a competent person scheme, GOV.UK, accessed 29 September 2026. gov.uk

  16. Competent person scheme: current schemes and how schemes are authorised, GOV.UK, accessed 29 September 2026. gov.uk

  17. The Building Regulations 2010, regulation 20: Provisions applicable to self-certification schemes, legislation.gov.uk, accessed 29 September 2026. legislation.gov.uk