UK Building Regulations & Compliance: Parts A-S Guide

Quick Answer: UK Building Regulations are set out in the Building Regulations 2010, with technical guidance in Approved Documents A to S. Most domestic work needs either a Building Notice or Full Plans submission to a Building Control Body, unless it falls under Schedule 2 exemptions or is self-certified by a Competent Person Scheme installer. The Building Safety Act 2022 added a separate regime for Higher-Risk Buildings (HRBs) above 18m or seven storeys.

What this guide covers

Building Regulations are the minimum standards for the design, construction and alteration of buildings in England and Wales. They sit alongside, but separate from, the planning system. Planning is about whether you can build something. Building Control is about whether what you have built is safe, accessible, energy-efficient and properly drained. A loft conversion can have planning permission and still fail Building Control sign-off, and that distinction confuses customers every week.

The legal basis is the Building Act 1984 and the Building Regulations 2010 (SI 2010/2214), amended many times since. The technical "how to comply" guidance lives in the Approved Documents, currently lettered A through S. They are not the law itself. You can comply by following them, or you can comply by demonstrating an alternative approach to the satisfaction of your Building Control Body (BCB). In practice, almost everyone follows the Approved Documents because that is what BCBs are trained to inspect against.

This guide is written for tradespeople and small builders who need to know which Approved Documents apply to a typical UK job, when Building Control sign-off is actually required, when you can self-certify under a Competent Person Scheme, and how the system has changed since the Grenfell Tower fire prompted the Building Safety Act 2022. For the full split between planning and building control, see the differences between Planning Permission and Building Regulations.

The Approved Documents A to S: what each one covers

The Approved Documents are issued by the Secretary of State and updated piecemeal, which is why some are dated 2010 and others 2022. Each one corresponds to a "Part" of Schedule 1 to the Building Regulations 2010. Part A covers structure, Part B fire safety, Part C site contamination and moisture, and so on. A loft conversion typically engages Parts A, B, K, L and P at minimum. A single-storey rear extension usually engages A, B (means of escape if it affects the existing layout), C, F, H, K, L and M.

For structural work, Approved Document A tells you when you need a structural engineer and what calculations are acceptable. For fire safety in dwellings, Part B sets out escape routes, compartmentation and fire-door specifications, with stricter requirements for loft conversions and three-storey homes. Part C deals with site contamination, ground moisture and DPC detailing, which matters on infill plots and brownfield work.

Service-related parts get most of the day-to-day attention. Approved Document F sets ventilation requirements for dwellings, including the 2022 changes that pushed background ventilator equivalent areas up sharply. Part G covers cold and hot water safety, with G3 unvented hot water systems requiring a separate qualification before you can install one. Part H covers above- and below-ground drainage, including septic tanks and rainwater. Part J covers combustion appliances, flues and hearth detailing for solid fuel, gas and oil.

The energy and accessibility parts are the ones that have changed most this decade. Part L on conservation of fuel and power tightened U-values for replacement elements in the 2021 edition and now interacts with SAP 10.2 calculations for new dwellings. Part M Volume 1 covers access to and use of dwellings, with three optional standards (M4(1), M4(2) and M4(3)) that planning authorities can require through local plans. Part M dwelling standards are increasingly written into Section 106 agreements for new estates.

The less famous parts still bite. Part K covers stairs, ramps, guarding and barriers, including pitch limits and 100mm sphere rules for balustrades. Part N on glazing safety in critical locations still applies, although it has been folded into Part K guidance in some jurisdictions. Part O on overheating in new residential buildings arrived in 2022 and now requires either simplified or dynamic thermal modelling. Part P covers notifiable electrical work in dwellings, which is where most cowboy electrical work gets caught at conveyancing. Approved Document Q sets PAS 24:2022 requirements for doors and ground-floor windows on new dwellings, and Part R requires gigabit-ready broadband infrastructure on most new builds since 2022. The newest, Part S on electric vehicle charging, requires a 7kW charge point or cable route for every new dwelling with associated parking.

Building Control: Local Authority vs Approved Inspector

Every building project that needs sign-off must use a Building Control Body. You can choose either Local Authority Building Control or a registered Approved Inspector. Local Authority Building Control (LABC) is run by the council. Approved Inspectors are private firms registered with the Construction Industry Council (CIC) since the Building Safety Act 2022 brought them under the Building Safety Regulator.

The choice is not just cost. LABC tends to be cheaper on small domestic work and has statutory enforcement powers, including the ability to serve Section 36 notices requiring removal or alteration of non-compliant work. Approved Inspectors are often faster to book site visits, more commercially flexible on staged inspections, and may have specialist expertise (for example, in heritage or timber frame). For high-volume housebuilders, Approved Inspectors are the norm because they will travel and inspect at short notice.

There are two routes into the system. A Building Notice is the fast route for straightforward domestic work, with no plans required upfront. A Full Plans submission gives you a formal decision on the design before you start, which matters when a mortgage lender or warranty provider wants written approval. This guide explains when each route is required and when you can skip Building Control entirely.

For repeat domestic work like rewires, boiler swaps, window replacements and gas appliance installs, the system is different. Competent Person Schemes such as NICEIC, Gas Safe, FENSA and OFTEC let registered installers self-certify their own work and notify Building Control on the customer's behalf, usually within 30 days. This avoids the inspection process entirely. It also leaves the installer personally liable for compliance, which is why scheme membership and insurance matter.

Exemptions, regularisation and when you don't need approval

Not every job needs Building Control. Schedule 2 to the Building Regulations 2010 lists exempt buildings and works. Schedule 2 exemptions include detached buildings under 30m² with no sleeping accommodation, small porches under 30m², small conservatories on existing dwellings, and certain agricultural buildings. The exemption rules are narrow and easily breached. A conservatory becomes non-exempt the moment it shares heating with the main house or removes the separating door. The detailed exemption criteria sit in Schedule 2 with very specific size, use and location limits.

When work has been done without Building Control approval, the route back is a Regularisation Certificate from the local authority. This is a retrospective application that allows the council to inspect existing work, require opening-up where needed, and issue a certificate if the work meets (or is brought up to) current standards. Approved Inspectors cannot issue regularisation certificates. Only the local authority can. This is the route conveyancing solicitors push for when a buyer's surveyor flags unauthorised work.

If a Building Control decision goes against you and you think it is wrong, there is a formal appeals process via the Secretary of State under Section 21 of the Building Act 1984. Determinations and dispensations have specific procedures. In practice, most disagreements are resolved informally with the inspector before anyone reaches for an appeal.

Building Safety Act 2022 and Higher-Risk Buildings

The Grenfell Tower fire in 2017 triggered the most significant rebuild of the regulatory system in 40 years. The Building Safety Act 2022 created a new Higher-Risk Buildings regime for residential buildings over 18m or seven storeys, with a "Gateway" approval process administered by the Building Safety Regulator (part of the Health and Safety Executive). HRB work cannot start without Gateway 2 approval, cannot complete without Gateway 3 sign-off, and cannot be occupied without Building Safety Regulator registration.

The Act also extended the Defective Premises Act 1972 limitation period from six to 30 years for cladding work completed before 2022, and to 15 years prospectively. This is why building safety insurance is now harder to get and more expensive. For tradespeople, the main practical effect is the "golden thread" duty: information about a higher-risk building must be maintained digitally throughout its life, and you may be asked to provide as-built records, product test data and installation evidence as part of handover. Outside the HRB tier, the Act tightened Building Control more generally, including the registration regime for Approved Inspectors and the new dutyholder requirements that mirror CDM 2015.

CDM 2015 and the construction phase plan

Construction (Design and Management) Regulations 2015 apply to almost every construction project, including domestic ones, but the duties differ by project size. CDM 2015 places duties on clients, designers, principal contractors and contractors from the moment a project is conceived. For domestic projects, the client's duties pass to the contractor or, if multiple contractors, to the principal contractor. The trap is the construction phase plan: it is required on every project, not just notifiable ones over 30 days or 500 person-days.

For small builders, the practical CDM compliance package is a written construction phase plan, an F10 notification to the HSE on larger jobs, RAMS for high-risk activities, and proper coordination where multiple trades are on site simultaneously. Failure to produce a construction phase plan on demand is the single most common HSE enforcement action against small builders.

Planning permission and the parallel system

Planning and Building Regulations are run by different teams in the same council, but they are legally separate. You can have one without the other. The distinction matters because the timelines and risks differ. Planning is discretionary, Building Regulations are mandatory.

Many domestic projects fall under Permitted Development Rights in the GPDO 2015 and need no planning application at all, although they still need Building Regulations approval. Single-storey rear extensions under 4m on a detached house are typically PD, subject to the neighbour consultation scheme. Planning application fees changed in April 2026 and now sit above £300 for a typical householder application.

Heritage constraints override most PD rights. Conservation area designation removes PD rights for cladding, side extensions and roof alterations. Listed Building Consent is a separate statutory consent required for any work affecting the special interest of a listed building, including internal works, and is a criminal offence to skip. If a planning application is refused, the appeals process via the Planning Inspectorate has different success rates depending on procedure (written representations, hearing or inquiry).

Party Wall Act and shared boundary work

The Party Wall etc. Act 1996 is not part of Building Regulations but is in the same family of statutory compliance that catches small builders. Notifiable work includes excavating within 3m of a neighbour's wall to a depth below their foundations, cutting into a shared wall, and building on the line of junction. Notice must be served between two months and one year before work starts, depending on the work type. Skipping the notice does not invalidate the work but exposes the building owner to injunctions and damages claims.

Specialist regimes: HMOs, landlord certificates and warranties

If your customer is a landlord, the compliance burden is wider than Building Regulations. HMO licensing applies to most properties with five or more occupants from two or more households, with mandatory and additional licensing schemes varying by council. HMO fire safety requirements include LD2 detection coverage and 30-minute compartmentation between flats and escape routes. Fire risk assessments are mandatory for common parts of HMOs and flats under the Regulatory Reform (Fire Safety) Order 2005, amended by the Fire Safety Act 2021.

Landlords also need ongoing certificates that tradespeople often supply. Gas Safety, EICR and EPC are the three core landlord certificates, with the Electrical Safety Standards in the Private Rented Sector Regulations 2020 requiring a five-yearly EICR. MEES regulations from April 2025 are pushing the minimum EPC band to C for new tenancies, with C for all tenancies from 2028 still proposed at the time of writing.

For warranties, the NHBC Buildmark 10-year warranty remains the de facto standard for new-build housing, although alternatives from Premier Guarantee, LABC Warranty and Build-Zone are widely accepted by mortgage lenders. For workmanship guarantees, Insurance-Backed Guarantees (IBGs) sit on top of competent person scheme work and cover the customer if your business ceases to trade.

Tax, payroll and labour compliance

The compliance load on a small builder is not only technical. The Construction Industry Scheme requires deductions from subcontractor payments at 0%, 20% or 30%, with monthly returns to HMRC. Right to Work checks on subcontractors are mandatory and now must be conducted using the Home Office's online service for share-code holders. The penalty is up to £20,000 per worker and, for repeat or knowing breaches, a criminal offence.

For self-build customers, self-builders carry the Building Regulations duties personally unless they appoint a principal contractor. The self-build VAT reclaim under VAT Notice 431NB has strict rules about which materials and services qualify.

Grants and incentives that affect compliance scope

Grant-funded work changes the compliance picture because the grant terms often require specific certifications. BUS, ECO4 and GBIS grants require MCS-certified installers and TrustMark registration for the contractor. Where a homeowner has applied for an ECO4 measure, you may need PAS 2035 retrofit coordination on top of the standard Building Regulations process.

Common questions

Do I need Building Regulations approval for a new bathroom?

A new bathroom in an existing home usually engages Parts G (water and sanitation), H (drainage) and L (energy if you add ventilation or replace windows). If you are only replacing fittings like-for-like with no changes to drainage or ventilation, you generally do not need Building Control. If you add a soil pipe, move a stack, install an unvented hot water cylinder, or create a new bathroom where none existed, you do. G3 unvented work is notifiable and must be done by a competent person.

Can my electrician self-certify without notifying Building Control?

Yes, if they are registered with a Part P Competent Person Scheme such as NICEIC, NAPIT, ELECSA or Stroma. They self-certify the work and notify Building Control on the customer's behalf, with a certificate issued within 30 days. If they are not scheme-registered, notifiable electrical work in a dwelling must be notified to the local authority before work starts, with a fee and an inspection by a third-party electrician.

What happens if work is done without Building Control approval?

It does not become unsafe by virtue of being unauthorised, but it cannot legally be sold without a Regularisation Certificate or an indemnity policy at conveyancing. Local authorities have 12 months from completion to prosecute for non-compliance, but the civil consequences (Section 36 notice requiring alteration or demolition) have no time limit. Most buyers' solicitors will require either a Regularisation Certificate or an indemnity, depending on age and risk.

Does an Approved Inspector's certificate carry the same weight as LABC?

Yes. A Final Certificate from a registered Approved Inspector is treated as evidence of compliance in the same way as a Local Authority Completion Certificate. Mortgage lenders, conveyancers and insurers accept both. The legal difference is enforcement: only the local authority can serve a Section 36 notice. An Approved Inspector who finds non-compliance must "cancel" their initial notice, which throws the work back to the local authority.

When does the Building Safety Act 2022 apply to my job?

The Higher-Risk Buildings regime applies to occupied residential buildings over 18m or seven storeys with at least two residential units. Below that height, the general Building Regulations changes apply: stricter inspection regimes, dutyholder duties that mirror CDM, and the registered Building Inspector requirement that came in October 2023. Most small domestic builders are affected by the dutyholder duties, not the HRB Gateway process.

Where to start

  1. Identify which Approved Documents your job actually engages. Most domestic projects hit five to eight. Read the relevant sections of each before pricing the job, not after.
  2. Decide your Building Control route early. Building Notice is faster for simple work. Full Plans gives you written approval before you start and is required by some lenders and warranties.
  3. Confirm whether any work is notifiable under a Competent Person Scheme. If it is and you are not registered, either subcontract to a registered installer or notify Building Control directly with a fee.
  4. Produce a written construction phase plan for every job, including domestic ones. It does not need to be long, but it must exist. Keep it on site.
  5. Check planning separately. PD does not exempt you from Building Regulations, and vice versa. Listed building and conservation area constraints override almost everything else.

Regulations and standards summary