Reference · England

Every figure, with the clause it came from.

295 rules across 17 Approved Documents, plus the control process, the surrounding statutes and the four routes to approval. This is the working reference our own site staff use, published as it stands — read out of the primary documents rather than recalled, and cited so you can go and check it.

If you want the plain-English version — do I need building control, what applies to my job, what happens on site — start with building control, explained. This page is the detail behind it.

The single most important distinction. The Building Regulations 2010 are the law. The Approved Documents are statutory guidance showing one way of meeting the law. Compliance is judged against the Requirements in Schedule 1 — reproduced at the head of each Part below — not against the guidance. You may depart from an Approved Document if you can demonstrate compliance another way, and your building control body has the final word on your specific building.

Before anything else

The four routes, and what each one protects you from.

Which route you choose changes what protection you get, and when you may start.

Full plans (local authority)

Deposit full plans with the local authority. The authority must pass or reject the plans; it must consult the fire authority and, where appropriate, the sewerage undertaker. You get a formal decision on the plans before you build, which is the safest route on anything structurally or legally contentious.

Local authority must decide within 5 weeks, or 2 months where the applicant agrees an extension.
Work may start after the authority has had at least two clear working days' notice.
If plans have not been assessed and approved when work starts, the work is deemed 'at risk'.
A completion certificate is issued where the authority is satisfied the work complies.

Building notice (local authority)

A short notice with no detailed plans. Quicker to start, but you get no plan approval and therefore no protection — any non-compliance is found on site, after it has been built. Not available for work subject to the Regulatory Reform (Fire Safety) Order or for building over a sewer.

Additional plans and details may be requested by the local authority at any time.
Work may start after two clear working days' notice.
No plans decision is issued, so all risk of non-compliance sits with the builder and the client.

Approved inspector (private)

An initial notice is given jointly by the approved inspector and the client to the local authority. Control passes from the local authority to the approved inspector.

If the local authority does not reject the initial notice within five working days of receipt, it is presumed accepted unconditionally.
The approved inspector must consult the fire authority and, where appropriate, the sewerage undertaker.
A plans certificate or final certificate cannot be issued until 15 working days have elapsed after that consultation.
A final certificate replaces the local authority completion certificate.

Competent person scheme

Certain work may be self-certified by an installer registered with an approved scheme. No notice to the local authority is required; the scheme notifies on the installer's behalf and issues the certificate to the client.

Gas — Gas Safe Register (a legal requirement, not merely a scheme).
Electrical — NICEIC, NAPIT, ELECSA, Stroma and others (Part P).
Replacement windows and doors — FENSA, CERTASS.
Solid fuel — HETAS. Oil — OFTEC.
A building control body and a competent person scheme can be used on the same project.

Search every rule295 rules

What counts as building work

If it is on this list, the Building Regulations apply and someone has to be notified — unless it is exempt or covered by a competent person scheme.

Topic	The rule — exact figures	Source
Erection or extension	Erecting or extending a building.	reg. 3(1)(a)
Controlled services and fittings	Providing, extending or otherwise materially altering a controlled service or fitting — heating, hot water, drainage, ventilation, electrics, windows and doors.	reg. 3(1)(b)
Material alteration	Work that would, at any stage, result in a building being less compliant than before with Parts A, B1–B5, M, or the access provisions.	reg. 3(1)(c) and reg. 4(2)
Material change of use	Work required because of a material change of use.	reg. 3(1)(d)
Cavity wall insulation	Inserting insulating material into the cavity of a cavity wall.	reg. 3(1)(e)
Underpinning	Underpinning a building.	reg. 3(1)(f)
Change of energy status	Work that changes a building's energy status.	reg. 22
Renovation of a thermal element	Renovating a thermal element — including re-rendering, re-roofing or re-plastering more than 50% of the element's surface.	reg. 23
Class 1	Buildings controlled under other legislation — explosives, nuclear installations, ancient monuments.
Class 2	Buildings not frequented by people — detached buildings into which people do not normally go, or go only intermittently for plant maintenance, sited at least one and a half times their height from any building people do go into.
Class 3	Greenhouses and agricultural buildings, subject to conditions (not used as a dwelling, sited at least one and a half times its height from any building containing sleeping accommodation, with a fire exit not more than 30 m from any point).
Class 4	Temporary buildings — intended to remain erected for less than 28 days.
Class 5	Ancillary buildings — site huts and buildings on construction sites, and buildings for selling on a site.
Class 6	Small detached buildings — a detached single-storey building with a floor area not exceeding 30 m² containing no sleeping accommodation, and either sited more than 1 m from the boundary or constructed substantially of non-combustible material; also a detached building not exceeding 30 m² designed to shelter people from nuclear radiation.
Class 7	Extensions — a ground-level extension by way of a conservatory, porch, covered yard, covered way or carport open on at least two sides, with a floor area not exceeding 30 m². Note: conservatories and porches must still have safety glazing (Part K) and must not obstruct access to a boiler or restrict escape.

Notifiable inspection stages

Each of these closes permanently once the work is covered. Miss one and the only remedy is opening up.

Topic	The rule — exact figures	Source
Commencement	At least two clear working days' notice before work starts.
Excavation for foundations	Before the excavation is covered — this is the inspection that fixes foundation depth.
Foundation concrete	Before it is covered.
Damp-proof course	Before it is covered.
Oversite / material laid over the site	Before it is covered.
Drains	Before backfilling, and again on testing.
First fix / pre-plaster	Structure, fire-stopping, cavity barriers, insulation and services before they disappear behind plasterboard.
Completion	Notice within five days of completion. The completion certificate follows.
Occupation before completion	Where a building is occupied before completion, notice must be given at least five days beforehand.

Enforcement, and what happens when it goes wrong

Topic	The rule — exact figures	Source
Prosecution	The local authority may prosecute in the magistrates' court, where an unlimited fine may be imposed.	Building Act 1984, ss.35 and 35A
Section 36 notice	The authority may require work to be pulled down, removed or made compliant. A s.36 notice cannot be served more than 12 months after the completion of the work.	Building Act 1984, s.36
Regularisation	Where unauthorised building work has been carried out since 11 November 1985, the owner may apply for a regularisation certificate. Opening up may be required.	reg. 18
Who is liable	Enforcement can be taken against the building owner and those carrying out the works. The duty to comply sits with clients, designers, builders and installers alike.	Manual, §B8–B12

Building Safety Act 2022 and the dutyholder regime

The regime that changed after Grenfell. The dutyholder duties apply to all building work, not only higher-risk buildings.

Topic	The rule — exact figures	Source
Higher-risk building	A building at least 18 m in height or with at least 7 storeys, containing at least 2 residential units. Hospitals and care homes are higher-risk during design and construction.	Building Safety Act 2022 / HRB Regs 2023
Gateway 1	Planning stage — a fire statement must accompany the planning application for a relevant building.	Building Safety Act 2022
Gateway 2	Before construction begins, the Building Safety Regulator must approve the application. Hard stop — work cannot start without it.	Building Safety Act 2022
Gateway 3	Before occupation, a completion certificate must be issued by the Building Safety Regulator and the building registered.	Building Safety Act 2022
Golden thread	Information about the building's design, construction and safety must be created, maintained and handed on in a structured digital form.	Building Safety Act 2022
Dutyholders	Client, principal designer, principal contractor, designers and contractors have statutory competence and coordination duties for all building work, not only higher-risk buildings, from 1 October 2023.	Building Regulations etc. (Amendment) (England) Regulations 2023
Building Safety Levy	From 1 October 2026, a levy on English residential development, charged per m². Developments of fewer than 10 units are exempt. Rates vary by local authority area, broadly £12–£100/m².	Building Safety Act 2022, Part 4

The law that runs alongside building control

Building Regulations approval is not a defence to any of these. Each has its own notice period and its own penalty.

Topic	The rule — exact figures	Source
Party Wall etc. Act 1996	Notice must be served before work starts. s.1 building on the line of junction (1 month). s.2 work to a party wall — 2 months' notice. s.6 excavation within 3 m going deeper than the neighbour's foundations, or within 6 m cutting a 45° line beneath them — 1 month's notice.
CDM 2015	Principal Designer and Principal Contractor are statutory roles where there is more than one contractor. F10 notification to HSE where work lasts more than 30 working days with more than 20 workers simultaneously, or exceeds 500 person-days. Excavations must be supported so they cannot collapse (reg. 22). Health and Safety File handed to the client at the end.
Control of Asbestos Regulations 2012	Any building constructed or refurbished before 2000 should be treated as potentially containing asbestos until shown otherwise. Reasonable steps must be taken to identify asbestos-containing materials before work liable to disturb them (reg. 5); a refurbishment and demolition survey is the normal means.
Water Supply (Water Fittings) Regulations 1999	All plumbing must comply — backflow prevention, approved fittings, notification of certain installations to the water undertaker.
Environmental Protection Act 1990, s.34	Duty of care for construction and demolition waste — transfer only to an authorised person, with a written description.
Wildlife and Countryside Act 1981 / Conservation of Habitats Regs 2017	Bats and nesting birds are protected. A roof or loft conversion in an older building may need a bat survey before work starts.
Planning Acts	Separate from Building Control entirely. Planning permission and Building Regulations approval are two different consents; having one never implies the other.

Structure

2004 edition, 2013 amendments

A1 · LoadingThe building shall be constructed so that the combined dead, imposed and wind loads are sustained and transmitted to the ground safely, and without causing such deflection or deformation of any part of the building, or such movement of the ground, as will impair the stability of any part of another building.

A2 · Ground movementThe building shall be constructed so that ground movement caused by swelling, shrinkage or freezing of the subsoil, or landslip or subsidence, will not impair the stability of any part of the building.

A3 · Disproportionate collapseThe building shall be constructed so that in the event of an accident the building will not suffer collapse to an extent disproportionate to the cause.

Topic	The rule — exact figures	Source
Foundation depth — frost	Strip foundations should have a minimum depth of 0.45 m to their underside, except where founded on rock. Increase in areas of long frost or to reach satisfactory ground.	AD A §2E4
Foundation depth — shrinkable clay	On clay with Modified Plasticity Index ≥ 10%: not less than 0.75 m (low shrinkage), 0.9 m (medium), 1.0 m (high). Increase where trees are nearby.	AD A §2E4
Strip foundation width	Concrete strip foundations should project each side of the wall by at least the depth of the foundation below the wall face, and the thickness must be not less than the projection, and never less than 150 mm.	AD A §2E2–2E3
Cavity wall leaves	Leaves at least 90 mm thick; cavity at least 50 mm wide.	AD A §2C8
Wall tie spacing	900 mm horizontal × 450 mm vertical, or not less than 2.5 ties/m². Additional ties not more than 300 mm apart vertically within 225 mm of the vertical edges of all openings, movement joints and roof verges.	AD A §2C8
Wall tie specification	Ties to BS EN 845-1, material reference 1 or 3 (austenitic stainless steel). Embedment not less than 50 mm in both leaves.	AD A §2C19, Table 5
Tie length by cavity	50–75 mm cavity → 200 mm tie · 76–100 → 225 · 101–125 → 250 · 126–150 → 275 · 151–175 → 300. Over 175 mm: cavity width + 125 mm.	AD A Table 5
Lintel bearing	Bearing length 150 mm or greater. Where clear span is 1200 mm or less, may reduce to 100 mm. (Manufacturers commonly require 200 mm on longer spans — follow their data too.)	AD A §2C24(a)
Maximum floor span on a wall	6 m, measured centre to centre of bearing.	AD A §2C23
Loading limit at wall base	Combined dead and imposed load should not exceed 70 kN/m at the base of the wall.	AD A §2C24(c)
Ground level difference	Difference in level of ground either side of a wall should be less than 4 × the wall thickness.	AD A §2C24(b)
Building height limit	Height from lowest finished ground level to the highest point of any wall or roof not greater than 15 m.	AD A §2C16
Wall length and height	Section does not cover walls longer than 12 m between restraints, or exceeding 12 m in height.	AD A §2C17
Minimum wall thickness	Wall ≤3.5 m high, ≤12 m long → 190 mm. 3.5–9 m high, ≤9 m long → 190 mm. Over 9 m → 290 mm from the base for one storey, 190 mm above.	AD A Table 3
Small single-storey walls	Single leaf of external walls of small single-storey non-residential buildings and annexes need only be 90 mm thick.	AD A §2C13
Maximum floor area	No floor enclosed by structural walls on all sides exceeds 70 m²; no floor without a structural wall on one side exceeds 36 m².	AD A §2C14
Imposed loads	Roof 1.00 kN/m² (spans ≤12 m) or 1.5 kN/m² (spans ≤6 m). Floors 2.00 kN/m². Ceilings 0.25 kN/m² plus a 0.9 kN concentrated load.	AD A Table 4
Annexes and small buildings	Height H not exceeding 3 m and greatest length/width W not exceeding 9 m.	AD A §2C16
Brick vs block	Brick = work size not exceeding 337.5 mm long or 112.5 mm high. Block exceeds either, minimum height 190 mm.	AD A Table 6 notes
Masonry unit voids	Group 1 units have not more than 25% formed voids (20% for frogged bricks). Group 2: greater than 25% but not more than 55%.	AD A Table 6 notes
Masonry unit standards	Clay BS EN 771-1 · calcium silicate 771-2 · concrete 771-3 · aerated concrete 771-4 · manufactured stone 771-5. Properly bonded and solidly put together with mortar.	AD A §2C20
Engineering brick classes	Class B ≥ 75 N/mm² compressive strength, ≤7% water absorption. Class A ≥ 125 N/mm², ≤4.5%. (UK National Annex — not in AD A itself.)	BS EN 771-1 UK NA
Roof pitch and bracing	Diagonal rafter bracing should be considered especially for single-hipped and non-hipped roofs of greater than 40° pitch to detached houses.	AD A, note to §2B
Disproportionate collapse	Applies to buildings of 5 storeys or more (Class 2B and above). Houses of 4 storeys or fewer are Class 1.	AD A §5, Table 11
Underpinning	Underpinning is designed by a structural engineer, executed in short designed bays in sequence, and the excavation is inspected before concrete is placed. Requirement A1 governs; there is no prescriptive AD A bay dimension.	Requirement A1 / BS EN 1997-1

Fire safety (Volume 1 dwellings · Volume 2 other buildings)

2019 edition, 2022 amendments

B1 · Means of warning and escapeThe building shall be designed and constructed so that there are appropriate provisions for the early warning of fire, and appropriate means of escape in case of fire from the building to a place of safety outside the building capable of being safely and effectively used at all material times.

B2 · Internal fire spread (linings)To inhibit the spread of fire within the building, internal linings shall adequately resist the spread of flame over their surfaces and have, if ignited, a rate of heat release or a rate of fire growth which is reasonable in the circumstances.

B3 · Internal fire spread (structure)The building shall be designed and constructed so that, in the event of fire, its stability will be maintained for a reasonable period. Walls common to two or more buildings shall resist fire spread; the building shall be sub-divided with fire-resisting construction; and concealed spaces shall be sealed and sub-divided to inhibit the unseen spread of fire and smoke.

B4 · External fire spreadThe external walls and roof shall adequately resist the spread of fire over the walls and from one building to another, having regard to the height, use and position of the building.

B5 · Access and facilities for the fire serviceThe building shall be designed and constructed so as to provide reasonable facilities to assist fire fighters in the protection of life, and reasonable provision shall be made within the site to enable fire appliances to gain access.

Topic	The rule — exact figures	Source
The 4.5 m rule	The storey height that changes everything in a house. Escape provisions step up at each storey more than 4.5 m above ground level — which is why a loft conversion on a two-storey house triggers a protected stair.	AD B Vol 1 §2.1–2.6
Single-storey / low houses	Dwellinghouse with upper storeys a maximum of 4.5 m above ground: escape via windows/doors from habitable rooms. No inner rooms allowed beyond the permitted arrangements.	AD B Vol 1 §2.2–2.3
Two or more storeys over 4.5 m	Provide a protected stairway, or alternative escape. Fire-resisting construction minimum REI 30; fire doorsets minimum E 30 (FD30).	AD B Vol 1 §2.5–2.6, Diagram 2.4
Escape window size	Openable area at least 0.33 m², at least 450 mm high and 450 mm wide, bottom of the openable area not more than 1100 mm above the floor.	AD B Vol 1 §2.10
Standard fire resistance in a house	REI 30 — 30 minutes load-bearing capacity, integrity and insulation — is the baseline for fire-separating construction in dwellinghouses.	AD B Vol 1, Table B4
Passenger lifts	A passenger lift serving any storey more than 4.5 m above ground level should be in the protected stairway enclosure or in a fire-resisting lift shaft.	AD B Vol 1 §2.7
Fire-stopping — the general rule	Every joint, imperfect fit and opening for services through a fire-separating element should be sealed with fire-stopping so the fire resistance of the element is not impaired.	AD B Vol 1 §9.1
Pipes through a fire wall	Three permitted routes: (A) proprietary tested sealing system, any diameter; (B) restricted diameter per Table 9.1; (C) sleeving.	AD B Vol 1 §9.2–9.5
Pipe diameter limits	Between flats or dwellinghouses: 160 mm high-melting-point metal · 160 mm stack / 110 mm branch for uPVC, lead, aluminium, fibre-cement in an enclosure · 40 mm any other material. Any other situation: non-metal drops to 40 mm.	AD B Vol 1 Table 9.1
Sleeving limit	Maximum nominal internal diameter 160 mm, sleeved in metal that will not soften or fracture at 800°C.	AD B Vol 1 §9.5
Smoke alarms	At least one on every storey. Grade D1 (mains with battery back-up), interlinked. Sited on the ceiling at least 300 mm from any wall or light fitting.	AD B Vol 1 §1.2–1.14
Cavity barriers	Provided at the edges of cavities, around openings, and to sub-divide extensive cavities. Not to be confused with fire-stopping.	AD B Vol 1 §8.1–8.6
Fire-stopping at roof level	Fire-stopping carried over the full thickness of the wall and up to the underside of the roof covering, boarding or slab, and extended into any eaves.	AD B Vol 1 §7.4, Diagram notes
Roof covering near a compartment wall	Roof covering designated BROOF(t4) for at least 1500 mm either side of the wall; wall to project at least 375 mm where required.	AD B, Diagram 12.x
Firefighting shafts	Required where any storey is more than 18 m above fire service vehicle access level, or a basement more than 10 m below it.	AD B Vol 2 §15.2
Compartment size	Storey exceeding 2000 m² divided by compartment wall (single-storey industrial examples); 30 m and 10 m maximum dimensions apply to specific diagram cases.	AD B Vol 2 §8, Diagrams
External stairs	Fire-resisting construction minimum RE 30 within 1800 mm of the stair, and 1100 mm above the top landing / 9 m below the flights and landings.	AD B Diagram 3.4
Rooflights	Maximum area 5 m² per rooflight or group, with a minimum 3 m between any two in any direction (1800 mm for Class D-s3,d2 rooflights in industrial and other non-residential groups where evenly distributed).	AD B Vol 2 §14.5–14.6
Small buildings exempt from spread limits	Conservatory, garage or outbuilding with a maximum floor area of 40 m²; detached swimming pool; balcony/carport with one longer side permanently open — boundary distances 6 m / 20 m apply.	AD B Tables 12.x
Fire-stopping materials	Reinforced with or supported by materials of the appropriate class. Proprietary tested systems may be used. Expanding foam alone is not fire-stopping.	AD B Vol 1 §9.25–9.27
Fire safety information at handover	Fire safety information must be given to the building owner on completion. This is a legal duty, not a courtesy.	Building Regulations 2010, reg. 38
Sprinklers in dwellings	Required in blocks of flats with a top storey more than 11 m above ground level (2020 amendment).	AD B Vol 1 §7.3
Combustible cladding ban	Materials in the external wall of a relevant building over 18 m must achieve Class A2-s1,d0 or better.	Building Regulations 2010, reg. 7(2)

Site preparation and resistance to contaminants and moisture

2004 edition, 2013 amendments

C1 · Site preparation and resistance to contaminantsThe ground to be covered by the building shall be reasonably free from any material that might damage the building or affect its stability, including vegetable matter, topsoil and pre-existing foundations. Reasonable precautions shall be taken to avoid danger to health and safety caused by contaminants on or in the ground, and adequate sub-soil drainage shall be provided if needed.

C2 · Resistance to moistureThe walls, floors and roof of the building shall adequately protect the building and people who use the building from harmful effects caused by ground moisture, precipitation including wind-driven spray, interstitial and surface condensation, and spillage of water from or associated with sanitary fittings or fixed appliances.

Topic	The rule — exact figures	Source
Damp-proof course — the barrier	Bituminous material, polyethylene, engineering bricks or slates in cement mortar, or any other material that will prevent the passage of moisture. Continuous with any damp-proof membrane in the floor.	AD C §5.5(a)
DPC height	On an external wall, the damp-proof course should be at least 150 mm above the level of the adjoining ground.	AD C §5.5(b)
Cavity depth below DPC	The cavity should be taken down at least 225 mm below the level of the lowest damp-proof course, or a damp-proof tray provided.	AD C §5.5(c)
Weep holes	Where a damp-proof tray is used, provide weep holes every 900 mm. Where the tray does not run the full length of the wall — i.e. above an opening — provide stop ends and at least two weep holes.	AD C §5.5(c), Diagram 9b
Minimum cavity width	At least 50 mm. Where partially filled, the residual cavity should not be less than 50 mm.	AD C §5.11, §5.14
Solid wall resistance to rain	Brickwork or stonework at least 328 mm thick, dense aggregate blockwork at least 250 mm, lightweight or AAC blockwork at least 215 mm — plus rendering in two coats totalling at least 20 mm with a scraped or textured finish.	AD C §5.8
Render mix	One part cement, one part lime, six parts well-graded sharp sand (1:1:6) — or 1:0.5:4 for dense concrete aggregate blocks. Joints raked out to at least 10 mm where the wall is to be rendered.	AD C §5.9
Ground-supported floor	Unreinforced concrete at least 100 mm thick to mix ST1 (BS 8500) on compacted hardcore; or concrete/fine aggregate at least 50 mm thick on at least 300 µm (1200 gauge) polyethylene sheet with sealed joints.	AD C §4.6
Hardcore depth limit	If the hardcore bed is deeper than 600 mm, there is a risk of excessive settlement — a suspended floor slab is advised.	AD C §4.6 note
Suspended timber ground floor	Ventilated air space measuring at least 150 mm clear from the ground to the underside of the floor (or the insulation).	AD C §4.11
Sub-floor ventilation	Openings in two opposing external walls, not less than 1500 mm²/m run of external wall or 500 mm²/m² of floor area, whichever is greater. Ventilating pipes at least 100 mm diameter.	AD C §4.11, §4.13
Suspended concrete ground floor	In-situ concrete at least 100 mm thick containing at least 300 kg of cement per m³; reinforcement protected by at least 40 mm cover (in-situ).	AD C §4.12
Moisture-resistant flooring	In kitchens, utility rooms and bathrooms, boarding must be moisture resistant. Softwood boarding at least 20 mm thick, durable species or preservative treated.	AD C §4.15
Groundwater	Where the water table can rise to within 0.25 m of the lowest floor, drain the ground by gravity or safeguard the building by other effective means.	AD C §3.2
Radon	Basic protective measures where 3%–10% of homes are predicted at or above the Radon Action Level of 200 Bq/m³; full protective measures where more than 10%.	AD C §2.38 / BR 211
Landfill proximity	Special consideration on a landfill site, within 250 m of a landfill boundary, or within its sphere of influence.	AD C §2.24
Cold roof ventilation	Cold deck roofs must be ventilated. AD C defers to BS 5250: 10 mm continuous eaves gap for pitches over 15°, 25 mm for 15° or less, plus 5 mm at the ridge where the pitch exceeds 35° or the span exceeds 10 m.	AD C §6.11 / BS 5250
Roof and floor U-value for condensation	Roof designed so the U-value does not exceed 0.35 W/m²K at any point; ground floor 0.7 W/m²K at any point (surface condensation criterion, not the Part L limit).	AD C §6.14, §4.21
Sealing the ceiling	Gaps and penetrations for pipes and wiring into roof voids should be filled and sealed; an effective draught seal to loft hatches.	AD C §6.12
Wall / roof definition	Roof = any part of the external envelope at less than 70° to the horizontal. Wall = any opaque part at 70° or more.	AD C, Appendix A
Threshold slope	The sill leading up to a door threshold has a maximum slope of 15°.	AD C §5.34

Toxic substances

1992 edition, 2013 amendments

D1 · Cavity insulationIf insulating material is inserted into a cavity in a cavity wall reasonable precautions shall be taken to prevent the subsequent permeation of any toxic fumes from that material into any part of the building occupied by people.

Topic	The rule — exact figures	Source
Urea formaldehyde foam	The only substance Part D addresses. UF foam may give off formaldehyde fumes; the inner leaf must be a continuous barrier to minimise fume penetration.	AD D §1.1–1.4
Suitability of the wall	The wall should be assessed before filling in accordance with BS 8208-1, and the installation carried out to BS 5617 and BS 5618 by an operative registered under an approved scheme.	AD D §1.3
Practical note	In practice Part D is rarely engaged on modern work — but a cavity fill in an existing wall still needs the BS 8208-1 suitability assessment before injection.	AD D §1.3

Resistance to the passage of sound

2003 edition, 2015 amendments

E1 · Protection against sound from other parts of the building and adjoining buildingsDwelling-houses, flats and rooms for residential purposes shall be designed and constructed in such a way that they provide reasonable resistance to sound from other parts of the same building and from adjoining buildings.

E2 · Protection against sound within a dwelling-house etc.Dwelling-houses, flats and rooms for residential purposes shall be designed and constructed in such a way that internal walls between a bedroom or a room containing a water closet and other rooms, and internal floors, provide reasonable resistance to sound.

E3 · Reverberation in the common internal parts of buildings containing flats or rooms for residential purposesThe common internal parts of buildings which contain flats or rooms for residential purposes shall be designed and constructed in such a way as to prevent more reverberation around the common parts than is reasonable.

E4 · Acoustic conditions in schoolsEach room or other space in a school building shall be designed and constructed in such a way that it has the acoustic conditions and the insulation against disturbance by noise appropriate to its intended use.

Topic	The rule — exact figures	Source
New-build separating walls and floors	Airborne sound insulation ≥ 45 dB DnT,w + Ctr. Impact sound (floors only) ≤ 62 dB L'nT,w.	AD E Table 1a
Conversions (material change of use)	Airborne ≥ 43 dB DnT,w + Ctr. Impact ≤ 64 dB L'nT,w. The relaxation that applies to work in existing buildings.	AD E Table 1b
Internal walls and floors (E2)	Airborne sound insulation ≥ 40 dB Rw for internal walls between a bedroom or WC and other rooms, and for internal floors.	AD E Table 2
Pre-completion testing	Required unless the construction is a registered Robust Detail. Test sets: at least one set per group of up to 10 dwellings.	AD E §1.1–1.5
Robust Details	Registering a Robust Detail with Robust Details Ltd before work starts avoids pre-completion testing. Registration must precede construction.	AD E §0.6
Doors in E2 locations	Minimum mass per unit area 25 kg/m² or a minimum sound reduction index of 29 dB Rw, with good perimeter sealing including the threshold where practical.	AD E §2.26, §4.20
Floating floor perimeter	Leave a gap of approximately 5 mm between skirting and floating layer and fill with flexible sealant. Perimeter strip approx. 4 mm higher than the floating layer during construction.	AD E §3.81, §3.119
Resilient floor covering	Overall uncompressed thickness at least 4.5 mm, or a weighted reduction in impact sound pressure level DLw ≥ 17 dB.	AD E §4.x
Platform floating floor	Rigid boarding above resilient layers with DLw ≥ 29 dB, achieved both loaded and unloaded.	AD E §3.x
Reverberation in common parts (E3)	Method A or Method B calculation for entrance halls, corridors and stairwells serving flats.	AD E §7.1–7.4
Schools (E4)	Acoustic conditions to Building Bulletin 93 (BB93).	AD E §8 / BB93
Measurement precision	Sound pressure levels measured to 0.1 dB precision; adjacent one-third octave band difference no more than 6 dB in the source room.	AD E Annex B, §B2.4, §B2.18

Ventilation (Volume 1 dwellings · Volume 2 other buildings)

2021 edition, 2023 amendments

F1 · VentilationThere shall be adequate means of ventilation provided for people in the building.

Topic	The rule — exact figures	Source
Intermittent extract — kitchen	30 l/s where a cooker hood extracts to the outside; 60 l/s where there is no hood or it does not extract outside.	AD F Vol 1 Table 1.1
Intermittent extract — utility room	30 l/s.	AD F Vol 1 Table 1.1
Intermittent extract — bathroom	15 l/s.	AD F Vol 1 Table 1.1
Intermittent extract — sanitary accommodation	6 l/s (or purge ventilation as an alternative).	AD F Vol 1 Table 1.1
Cooker hood height	Between 650 mm and 750 mm above the hob surface where the manufacturer gives no figure. The hood should span at least the full width of the cooker.	AD F Vol 1 §1.21
Run-on timers	Set to at least 15 minutes.	AD F Vol 1 §1.x
Background ventilators — new dwellings	Habitable rooms minimum 8000 mm² equivalent area; kitchen 8000 mm²; bathroom (with or without WC) 4000 mm².	AD F Vol 1 §1.x
Background ventilators — replacement windows	Where a dwelling has continuous mechanical extract: minimum 4000 mm² equivalent area in each habitable room that is not a wet room.	AD F Vol 1 §3.x
Extensions and additional rooms	If the existing habitable room has less than 5000 mm² of background ventilator, follow §1.42–1.44. If at least 5000 mm², provide 12,000 mm² between the two rooms and 12,000 mm² between the new room and outside.	AD F Vol 1 §3.x
Conservatories	The guidance applies to conservatories with floor area exceeding 30 m². Conservatories not exceeding 30 m² are exempt from Part F.	AD F Vol 1 §3.21
Internal door undercut	Free area equivalent to a 10 mm undercut in a 760 mm wide door.	AD F Vol 1 §3.27
Purge ventilation	Openable area at least 1/20th of the floor area of the room served for a window opening 30° or more; 1/10th for less than 30°.	AD F Vol 1 §1.x
Air permeability trigger	Where design air permeability is <5 m³/(h·m²) at 50 Pa, continuous mechanical ventilation is expected. As-built target lower than 3 m³/(h·m²) triggers further measures.	AD F Vol 1 §1.x
Commissioning notice	Notice of commissioning given not more than 5 days after completion of commissioning where a building notice/full plans/initial notice applies, otherwise not more than 30 days after completion of the work.	AD F, reg. 42
Non-dwellings — occupied rooms	The greater of 10 l/s per person or 1 l/s per m² of floor area.	AD F Vol 2 §1.x
Non-dwellings — sanitary	15 l/s per shower or bath; 6 l/s per WC pan or urinal.	AD F Vol 2 §1.x
Non-dwellings — tea points and kitchens	Microwave/drinks only: 15 l/s. Extract adjacent to the hob: 30 l/s. Remote from the hob: 60 l/s.	AD F Vol 2 §1.x
Printers and photocopiers	Rooms in substantial use (more than 30 minutes per hour) should not be designed to be occupied; extract at 20 l/s per machine during use.	AD F Vol 2 §1.25
Air inlet position	As high as practicable and a maximum of 400 mm below the ceiling; at least 500 mm from people where practicable.	AD F Vol 2 §1.x
Indoor humidity criteria	Moving average relative humidity below 65% (1 month), 75% (1 week), 85% (1 day).	AD F Appendix B, Table B3

Sanitation, hot water safety and water efficiency

2015 edition, 2016 amendments

G1 · Cold water supplyThere must be a suitable installation for the provision of wholesome water to any place where drinking water is drawn off, and to any washbasin, bidet, fixed bath or shower.

G2 · Water efficiencyReasonable provision must be made by the installation of fittings and fixed appliances that use water efficiently for the prevention of undue consumption of water.

G3 · Hot water supply and systemsThere must be a suitable installation for the provision of heated wholesome or softened wholesome water; a hot water system with a storage vessel must have precautions to prevent the temperature of stored water exceeding 100°C and to safely discharge hot water; and the hot water supply to a bath must be limited.

G4 · Sanitary conveniences and washing facilitiesAdequate and suitable sanitary conveniences must be provided in rooms provided for that purpose, or in bathrooms, with washbasins in the immediate vicinity.

G5 · BathroomsA bathroom must be provided containing a washbasin and either a fixed bath or a shower.

G6 · Food preparation areasA suitable sink must be provided in any area where food is prepared.

Topic	The rule — exact figures	Source
Water efficiency — new dwellings	Potential consumption of wholesome water must not exceed 125 litres per person per day, or the optional requirement of 110 litres where imposed by a planning condition.	Building Regulations 2010, reg. 36 / AD G2
External water allowance	An allowance of 5 litres/person/day is added to the calculated total for external water use.	AD G Appendix A, §A7
Bath temperature — scalding	The hot water supply to a bath must be limited to a maximum of 48°C by an in-line blending valve or other temperature control device with a maximum temperature stop.	AD G §3.65–3.66
Unvented hot water storage	Must have the required safety devices and a correctly terminated discharge pipe; installation is work for a competent person.	AD G §3.22–3.23
Stored water temperature	Precautions to prevent the temperature of stored water at any time exceeding 100°C.	Requirement G3(3)
Discharge pipe — low level	Downward discharges at low level, up to 100 mm above external surfaces, are acceptable with a wire cage or guard positioned to prevent contact while maintaining visibility.	AD G §3.x
Discharge pipe — high level	Into a metal hopper and metal downpipe with the discharge end clearly visible, or onto a roof capable of withstanding high-temperature discharge and 3 m from any plastic guttering.	AD G §3.x
Commissioning notice	Not more than 5 days after completion of the commissioning work where a building notice/full plans/initial notice applies; otherwise not more than 30 days.	AD G §3.78
Tap flow measurement	Measured at a dynamic pressure of 3 ± 0.2 bar for high-pressure (Type 1) taps, or 0.1 ± 0.02 bar for low-pressure (Type 2).	AD G Appendix A
Assumed consumption defaults	Dishwasher 1.25 litres per place setting; washing machine 8.17 litres per kilogram; waste disposal unit 3.08 litres/person/day where actual figures are unknown.	AD G Appendix A
Legionella	For temperature limits to control legionella bacteria in domestic hot water systems, see AD G — stored water generally at 60°C, distributed at not less than 55°C.	AD G §3.x / HSG274
Statutory supply pressure (context)	Not a Building Regulation: water undertakers are held to 7 m static head (≈0.7 bar) at the communication pipe; Ofwat's low-pressure reference level is 10 m head at 9 l/min at the boundary stop tap.	Water Industry Act 1991 s.65 / Ofwat

Drainage and waste disposal

2015 edition

H1 · Foul water drainageAn adequate system of drainage shall be provided to carry foul water from appliances within the building to a foul water outfall.

H2 · Wastewater treatment systems and cesspoolsAny septic tank and its form of secondary treatment, other wastewater treatment system or cesspool, shall be constructed and sited so as not to be prejudicial to the health of any person, adequately constructed, ventilated and sited.

H3 · Rainwater drainageAdequate provision shall be made for rainwater to be carried from the roof of the building, and paved areas around the building shall be so constructed as to be adequately drained.

H4 · Building over sewersThe erection or extension of a building or work involving the underpinning of a building shall be carried out in a way that is not detrimental to the building or building extension or to the continued maintenance of the drain, sewer or disposal main.

H5 · Separate systems of drainageAny system for discharging water to a sewer which is provided pursuant to paragraph H3 shall be separate from that provided for the conveyance of foul water from the building.

H6 · Solid waste storageAdequate provision shall be made for storage of solid waste, and means of access for people in the building to the place of storage and for the waste to be removed to a collection point.

Topic	The rule — exact figures	Source
Foul drain minimum gradients	Peak flow <1 l/s: 75 mm pipe at 1:40 (capacity 4.1 l/s), 100 mm at 1:40 (9.2 l/s). Peak flow >1 l/s: 75 mm at 1:80 (2.8), 100 mm at 1:80 with minimum 1 WC (6.3), 150 mm at 1:150 with minimum 5 WCs (15.0).	AD H Table 6
Minimum drain size	A drain carrying foul water from a WC should have an internal diameter of at least 100 mm.	AD H §2.33
Rainwater drain gradients	75 mm and 100 mm rainwater drains not less than 1:100; 150 mm not less than 1:150; 225 mm not less than 1:225.	AD H §3.15
Trap seal depths	Washbasin, bidet, sink, food waste disposal, washing machine, dishwasher: 75 mm seal on a 32/40 mm trap. Bath, shower: 50 mm. WC with outlet <80 mm: 50 mm on 75 mm. Seal may reduce to 50 mm only with flush grated wastes without plugs.	AD H Table 1
Stack sizes	Stacks serving urinals not less than 50 mm; closets with outlets less than 80 mm not less than 75 mm; closets with outlets greater than 80 mm not less than 100 mm. Internal diameter not less than the largest trap or branch it serves, and must not reduce in the direction of flow.	AD H §1.28, Table 3
Branch connections	Junctions of about the same diameter made with a sweep of 25 mm radius or at 45°. Branches of 75 mm or more into a stack of equal diameter: sweep of 50 mm minimum radius or at 45°.	AD H §1.17
Branch ventilating pipes	At least 25 mm diameter; at least 32 mm where the branch is longer than 15 m or has more than 5 bends.	AD H §1.24
Boiler condensate	Connect using pipework of minimum diameter 22 mm through a 75 mm condensate trap.	AD H §1.14
Air test — sanitary pipework	Positive pressure of at least 38 mm water gauge held for at least 3 minutes; every trap must retain a water seal of at least 25 mm.	AD H §1.38
Air test — drains	Pipes up to 300 mm diameter pressurised to 110 mm water gauge, held ~5 minutes, then must hold an initial 100 mm pressure with maximum loss of 25 mm over 7 minutes.	AD H §2.60
Water test — drains	Test pressure maintained 30 minutes, topped up to within 100 mm of the required level. Loss not to exceed 0.15 l/m² for pipelines only, 0.20 l/m² including manholes.	AD H §2.x
Cover to drains	Thermoplastic pipes 100–300 mm: 0.6 m–7 m in fields, 0.9 m–7 m in light and main roads. Rigid pipes: 0.6 m minimum in fields, 1.2 m in roads.	AD H Tables 8–10
Percolation test	Excavate a hole 300 mm square to 300 mm below the invert of the distribution pipe. Next day refill to at least 300 mm depth and time the seepage from 75% to 25% full (a depth of 150 mm), in seconds.	AD H §1.34–1.36
Building over a sewer	Where a building is erected over or within 3 m of a public sewer, agreement with the sewerage undertaker is required; access must be maintained.	AD H4
Separate systems	Rainwater must not discharge to a foul-only system where a separate surface water system exists.	Requirement H5

Combustion appliances and fuel storage systems

2010 edition, 2013 amendments

J1 · Air supplyCombustion installations shall be so designed and installed that there is an adequate supply of air to them for combustion, to prevent overheating and for the efficient working of any flue.

J2 · Discharge of products of combustionCombustion installations shall have adequate provision for the discharge of products of combustion to the outside air.

J3 · Warning of release of carbon monoxideWhere a fixed combustion appliance is provided, appropriate provision shall be made to detect and give warning of the release of carbon monoxide.

J4 · Protection of buildingCombustion installations shall be so designed, installed and constructed as to reduce to a reasonable level the risk of people suffering burns or the building catching fire in consequence of their use.

J5 · Provision of informationWhere a hearth, fireplace, flue or chimney is provided or extended, a durable notice containing information on the performance capabilities shall be affixed in a suitable place in the building.

J6 · Protection of liquid fuel storage systemsLiquid fuel storage systems and the pipes connecting them to combustion appliances shall be so constructed and separated from buildings and the boundary of the premises as to reduce to a reasonable level the risk of the fuel igniting in the event of fire in adjacent buildings or premises.

J7 · Protection against pollutionOil storage tanks and the pipes connecting them to combustion appliances shall be so constructed and protected as to reduce to a reasonable level the risk of the oil escaping and causing pollution.

Topic	The rule — exact figures	Source
Flue size — open fireplace	Fireplace with an opening up to 500 × 550 mm: 200 mm diameter, or rectangular/square of the same cross-sectional area with minimum dimension not less than 175 mm.	AD J Table 2
Flue size — closed appliance	Closed appliance up to 30 kW burning any fuel: 150 mm diameter or equivalent with minimum dimension 125 mm. Above 30 kW and up to 50 kW: 175 mm diameter, minimum dimension 150 mm.	AD J Table 2
Flue size — gas fire	ILFE/DFE fire within an opening up to 500 × 550 mm: circular 125 mm diameter, or rectangular 12,000 mm² cross-section with minimum dimension 63 mm.	AD J Table 2
Permanently open air vents — open fire	Fireplace opening 500 mm → 20,500 mm²; 450 mm → 18,500 mm²; 400 mm → 16,500 mm²; 350 mm → 14,500 mm².	AD J Table 1 / Diagram
Air supply — other solid fuel appliances	Where design air permeability >5.0 m³/(h·m²): 300 mm²/kW for the first 5 kW and 850 mm²/kW for the balance. Where ≤5.0: 850 mm²/kW of rated output.	AD J Table 1
Flue outlet — at the ridge	At or within 600 mm of the ridge: at least 600 mm above the ridge.	AD J Diagram 17
Flue outlet — elsewhere on a roof	At least 2300 mm horizontally from the nearest point on the weather surface, and at least 1000 mm above it.	AD J Diagram 17
Flue outlet — near another building	Within 2300 mm of an adjoining or adjacent building: at least 600 mm above any part of that building within 2300 mm.	AD J Diagram 17
Carbon monoxide alarm siting	On the ceiling at least 300 mm from any wall, or high on a wall but not within 150 mm of the ceiling; and between 1 m and 3 m horizontally from the appliance.	AD J §2.34
Hearths — standard	Constructed of solid, non-combustible material. Where the appliance could raise the floor temperature below it above 100°C, provide a hearth of solid non-combustible material at least 125 mm thick.	AD J §4.26
Combustible material near a flue	At least 200 mm from the inside surface of a flue or fireplace recess, or 40 mm from the outer surface of a masonry chimney (except floorboards, skirting, dado, picture rail, mantel-shelf or architrave). Metal fixings in contact with combustible material at least 50 mm from the inside surface of a flue.	AD J §1.x
Oil tank fire separation	Tank less than 1800 mm from a building: make walls imperforate within 1800 mm with at least 30 minutes fire resistance, and eaves within 1800 mm extending 300 mm beyond each side with 30 minutes fire resistance and non-combustible cladding; or provide a fire wall.	AD J §5.x
Flue liner jointing	Clay or concrete flue liners must be correctly jointed with the socket end uppermost.	AD J §1.x / commissioning checklist
Balanced flue terminal	At least 1 m horizontally and 300 mm vertically from openings or heat sources such as flue terminals and tumble-dryer vents; at least 2 m horizontally from unsealed gullies or cellar hatches unless a wall not less than 250 mm high intervenes.	AD J §5.x
Notice plate (J5)	A durable notice must be permanently fixed — normally at the meter, consumer unit or hearth — recording the flue and hearth performance.	AD J §1.x

Protection from falling, collision and impact

2013 edition

K1 · Stairs, ladders and rampsStairs, ladders and ramps shall be so designed, constructed and installed as to be safe for people moving between different levels in or about the building.

K2 · Protection from fallingAny stairs, ramps, floors and balconies and any roof to which people have access, and any light well, basement area or similar sunken area connected to a building, shall be provided with barriers where it is necessary to protect people in or about the building from falling.

K3 · Vehicle barriers and loading baysVehicle ramps and any levels in a building to which vehicles have access, shall be provided with barriers where it is necessary to protect people in or about the building. Vehicle loading bays shall be constructed so as to protect people in them from collision with vehicles.

K4 · Protection against impact with glazingGlazing, with which people are likely to come into contact whilst moving in or about the building, shall if broken on impact, break in a way which is unlikely to cause injury; resist impact without breaking; or be shielded or protected from impact.

K5 · Protection from collision with open windows etc.Provision shall be made to prevent people moving in or about the building from colliding with open windows, skylights or ventilators.

K6 · Protection against impact from and trapping by doorsProvision shall be made to prevent any door or gate which slides or opens upwards from falling onto any person; and which opens towards a route of escape from causing injury.

Topic	The rule — exact figures	Source
Private stair — rise and going	Maximum rise 220 mm, minimum going 220 mm. Maximum pitch 42°.	AD K Table 1.1 and note [1]
Utility stair	Maximum rise 190 mm, minimum going 250 mm.	AD K Table 1.1
General access stair	Maximum rise 170 mm, minimum going 250 mm.	AD K Table 1.1
The 2R + G rule	Twice the rise plus the going should equal between 550 mm and 700 mm.	AD K Table 1.1 note
Tread overlap	Treads should overlap no more than 25 mm. Open riser treads should overlap at least 16 mm.	AD K §1.5–1.10, Diagram 1.2
Open risers	Construct so that a 100 mm diameter sphere cannot pass through the open risers.	AD K §1.10
Headroom — general	Minimum 2 m on the access between levels, measured from the pitch line.	AD K §1.11, Diagram 1.3
Headroom — loft conversions	Where 2 m cannot be achieved: 1.9 m at the centre of the stair width, reducing to 1.8 m at the side of the stair, is satisfactory.	AD K §1.13, Diagram 1.4
Stair width — dwellings	No statutory minimum for a private stair, but on severely sloping plots a flight within the entrance storey should be a minimum of 900 mm wide.	AD K §1.16
Flight length	If stairs have more than 36 risers in consecutive flights, make at least one change of direction between flights.	AD K §1.17
Landings	Level, with an unobstructed length of at least 1200 mm on each landing. Landings next to doors in dwellings: at least 400 mm clear.	AD K §1.22–1.24, Diagram 1.8
Tapered treads	Where the stair is less than 1 m wide, minimum tread width at the narrow end 50 mm. Going measured at the centre of the stair.	AD K §1.25–1.27, Diagram 1.9
Alternating tread stair	Minimum going 220 mm, maximum rise 220 mm, handrails to both sides. Only for loft conversions where there is only one room served.	AD K §1.29–1.30, Diagram 1.10
Handrail height	Top of the handrail 900 mm to 1000 mm from the pitch line or floor. Handrail on both sides if the stair is 1000 mm or wider.	AD K §1.34–1.35
Handrail profile	Circular 32 mm to 50 mm diameter; non-circular 50 mm wide and 39 mm deep with rounded edges (minimum 15 mm radius). Clearance at least 50 mm from the wall.	AD K Diagram 1.13
Guarding — when required	In dwellings, guard the sides of flights and landings where there is a drop of more than 600 mm. In other buildings, where a person could fall more than two risers or 380 mm.	AD K §1.41, §3.x
Guarding height	Stairs, landings, ramps and edges of internal floors in dwellings: 900 mm. External balconies and edges of roofs: 1100 mm. (See Diagram 3.1 for the full set.)	AD K Diagram 3.1
Guarding openings	A 100 mm sphere must not pass through any opening in the guarding, and children must not be able to climb it readily.	AD K §1.40, §3.3
Soffit under a stair	If the soffit beneath a stair or ramp is less than 2 m above floor level, protect the area beneath it (guarding or low-level cane detection).	AD K §1.8, §2.7
Ramp gradient	Maximum 1:12 for a going up to 2 m; 1:15 for a going up to 5 m; 1:20 for a going up to 10 m. Interpolate between (1:14 for 4 m, 1:19 for 9 m).	AD K §2.3, Diagram 2.1
Ramp width and landings	Minimum width between walls, upstands or kerbs 1500 mm. Landings at foot and head a minimum of 1200 mm long; intermediate landings a minimum of 1500 mm; passing places 1800 × 1800 mm.	AD K §2.x
Ramp kerb	Minimum 100 mm high, contrasting visually with the ramp or landing.	AD K §2.x
Ramp vs steps	Change of level 300 mm or more: provide two or more clearly signposted steps in addition to the ramp. Less than 300 mm: provide a ramp instead of a single step.	AD K §2.6
Critical glazing locations	Glazing below 800 mm from floor level in walls, and below 1500 mm in doors and side panels within 300 mm of the door edge.	AD K §5.1–5.2, Diagram 5.1
Safety glazing performance	In critical locations glazing must break safely, be robust, be small panes, or be permanently protected. Door and side panels with a pane width exceeding 900 mm: Class 2 of BS EN 12600 or Class B of BS 6206.	AD K §5.2
Manifestation of glazing	Large uninterrupted glazed areas must be marked so they are apparent — a permanent feature between 850 mm and 1000 mm and between 1400 mm and 1600 mm above floor level.	AD K §6.x
Vehicle barriers	Barrier at least 375 mm high for floors and roofs, 610 mm for ramps, loaded per BS EN 1991-1-1 with its UK National Annex.	AD K §4.1–4.2, Diagram 4.2

Conservation of fuel and power (Volume 1 dwellings · Volume 2 other buildings)

2021 edition, 2023 amendments

L1 · Conservation of fuel and powerReasonable provision shall be made for the conservation of fuel and power in buildings by: limiting heat gains and losses through thermal elements and other parts of the building fabric, and from pipes, ducts and vessels used for space heating, space cooling and hot water services; providing fixed building services which are energy efficient, have effective controls, and are commissioned by testing and adjustment as necessary.

Topic	The rule — exact figures	Source
New elements in existing dwellings — roof	Maximum U-value 0.15 W/(m²·K).	AD L Vol 1 Table 4.2
New elements in existing dwellings — wall	Maximum U-value 0.18 W/(m²·K).	AD L Vol 1 Table 4.2
New elements in existing dwellings — floor	Maximum U-value 0.18 W/(m²·K).	AD L Vol 1 Table 4.2
Windows	Maximum U-value 1.4 W/(m²·K), or Window Energy Rating Band B minimum.	AD L Vol 1 Table 4.2
Doors — more than 60% glazed	Maximum U-value 1.4 W/(m²·K), or Doorset Energy Rating Band C minimum.	AD L Vol 1 Table 4.2
Other doors	Maximum U-value 1.4 W/(m²·K), or Doorset Energy Rating Band B minimum. External fire doorsets may be 1.8.	AD L Vol 1 Table 4.2
Rooflights	Maximum U-value 2.2 W/(m²·K), based on the developed surface area. A site-built upstand should not exceed 0.35 W/(m²·K).	AD L Vol 1 Table 4.2
Replacement rule	The U-value of a replacement element must be no worse than the element being replaced and meet the Table 4.2 limiting standard.	AD L Vol 1 §4.8
Heritage relaxation	Where windows or fully glazed external pedestrian doors cannot meet Table 4.2 because of the need to maintain the character of the building: either a centre pane U-value not exceeding 1.2 W/(m²·K), or single glazing supplemented with low-emissivity secondary glazing.	AD L Vol 1 §4.10
Renovated / retained elements	Threshold and improved U-values in Table 4.3 — e.g. roof threshold 0.35, improved 0.16; cavity wall threshold 0.70. Once upgraded, a thermal element should generally not exceed 0.7 W/(m²·K).	AD L Vol 1 §4.11–4.13, Table 4.3
Payback test	If achieving the improved U-value is not technically or functionally feasible, or would not achieve a simple payback of 15 years or less, upgrade to the lowest U-value that is feasible and pays back within 15 years.	AD L Vol 1 §4.13
Low-temperature heating — the 55°C rule	Where a wet heating system is newly installed, or fully replaced in an existing building (appliance, emitters and pipework), all parts should be sized to operate effectively at a maximum flow temperature of 55°C or lower.	AD L Vol 1 §5.10
Zoning	Wet heating systems in new dwellings with a floor area of 150 m² or greater: a minimum of two independently controlled heating circuits.	AD L Vol 1 §5.14
Thermostatic room controls	In new dwellings, and when a heat generator is replaced in an existing dwelling, each room should have thermostatic room controls.	AD L Vol 1 §5.20
Underfloor heating controls	All UFH should have controls to adjust the operating temperature. Room thermostats for electric UFH should have a manual override. Screed floors thicker than 65 mm should automatically set back the temperature at night or when unoccupied.	AD L Vol 1 §6.28
UFH downward heat loss	Ground floors and floors in contact with the outside should be insulated to limit heat loss to not more than 10 W/m².	AD L Vol 1 §6.29
UFH insulation resistance	Intermittent/cyclical operation or over unheated rooms: at least 1.25 m²K/W. Per BS EN 1264-4: not less than 0.5 m²K/W (electric) and 0.75 m²K/W (wet).	AD L Vol 1 §6.30–6.31
Electric UFH screed depths	Direct electric systems within screeds not exceeding 60 mm. Night energy-storage systems within screeds of at least 65 mm, with at least 20% of the dwelling floor area on fast-response systems.	AD L Vol 1 §6.33–6.34
Hot water sizing	Sized to BS EN 12831-3 or the CIPHE Design Guide; systems should not be significantly oversized.	AD L Vol 1 §5.11
Air permeability	New dwellings must be tested; the limiting standard is 8 m³/(h·m²) at 50 Pa, with design targets typically far lower.	AD L Vol 1 §4.x
Consequential improvements	Buildings with a floor area over 1000 m² undergoing extension or an increase in fixed building services must make consequential improvements where technically and economically feasible.	Building Regulations 2010, reg. 28
Building log book / handover	Information about the building's services and their maintenance must be given to the owner on completion.	Building Regulations 2010, reg. 40

Access to and use of buildings (Volume 1 dwellings · Volume 2 other buildings)

2015 edition, 2016 amendments

M4(1) · Category 1 — Visitable dwellingsReasonable provision shall be made for people to gain access to, and use, the dwelling and its facilities.

M4(2) · Category 2 — Accessible and adaptable dwellingsReasonable provision shall be made for people to gain access to, and use, the dwelling and its facilities; and the provision made shall be sufficient to meet the needs of occupants with differing needs, including some older or disabled people, and to allow adaptation of the dwelling to meet the changing needs of occupants over time. Applies only where imposed as a planning condition.

M4(3) · Category 3 — Wheelchair user dwellingsAs M4(2), and in addition the dwelling must be wheelchair accessible, or easily adaptable for wheelchair users. Applies only where imposed as a planning condition.

M1–M3 · Buildings other than dwellingsReasonable provision shall be made for people to gain access to and use the building and its facilities; suitable independent access shall be provided to the extension where reasonably practicable; and if sanitary conveniences are provided in any building that is to be extended, reasonable provision shall be made within the extension for sanitary conveniences.

Topic	The rule — exact figures	Source
Private approach route	Minimum clear width 1200 mm, with a level landing area of 1500 × 1500 mm at the entrance.	AD M Vol 1 Diagram 1.1
Entrance door	Private main entrance door minimum clear opening width 850 mm. Garden gate 850 mm.	AD M Vol 1 Diagram 1.1
Nibs at the entrance	Nib to following edge 200 mm; nib to leading edge 300 mm; side clearance zone 300 × 1800 mm; canopy 1200 × 1200 mm.	AD M Vol 1 Diagram 1.1
Category 1 WC	Frontal or oblique access WC with the clear access zone shown — typical dimensions 450 mm from the WC centreline, 1050 mm × 750 mm activity space.	AD M Vol 1 Diagram 1.4
Category 2 — corridor and door widths	Minimum hall/landing width 900 mm (may reduce to 750 mm at a localised obstruction no more than 2 m long); door clear opening widths 750–850 mm depending on the approach.	AD M Vol 1 Diagram 3.4
Category 2 — WC/cloakroom	Layouts per Diagram 2.6: e.g. 1450 × 1000 mm or 1800 × 1000 mm with a 750 mm activity zone.	AD M Vol 1 Diagram 2.6
Category 2 — bathrooms	Examples at 2150 × 1900 mm and 2000 × 1700 mm with 450 mm and 300 mm clearances.	AD M Vol 1 Diagram 2.7
Category 3 — turning circle	1500 mm diameter clear turning circle, which may overlap with the shower.	AD M Vol 1 Diagram 3.10
Category 3 — bathroom sizes	Wheelchair accessible bathroom with bath and 1000 × 1200 mm shower, or bath and 1200 × 1200 mm shower. Wheelchair adaptable examples 2450 × 2200 mm and 2450 × 2600 mm.	AD M Vol 1 Diagrams 3.15–3.17
Basin encroachment	Maximum encroachment into the WC access zone: 200 mm for a hand rinse basin, 300 mm for a wash hand basin.	AD M Vol 1 Diagram 3.10
Services and controls height	Positioned between 450 mm and 1200 mm above floor level and at least 300 mm from an internal corner.	AD M Vol 1 §2.30
Wheelchair storage and transfer	Space to store and charge a wheelchair, plus a transfer space at the entrance.	AD M Vol 1 §3.25
Accessible WC cubicle (non-dwellings)	Minimum 1500 mm wide × 2200 mm deep with a 1500 mm turning circle; WC centreline 500 mm from the side wall; grab rails per Diagram 21.	AD M Vol 2 Diagram 21
Ambulant disabled cubicle	Minimum 1465 mm deep × 920 mm wide with horizontal and vertical grab rails and a horizontal closing bar.	AD M Vol 2 Diagram 21
Bathroom turning circle (non-dwellings)	The bathroom (or bathrooms) provides a minimum 1500 mm clear turning circle.	AD M Vol 2 §3.x
Approach route (non-dwellings)	Minimum 900 mm wide with a maximum cross fall of 1 in 40. Private parts of the approach: minimum clear width 900 mm, or 750 mm where constrained.	AD M Vol 2 §1.x
Vehicle access door	Every elevation to which vehicle access is provided should have a door a minimum of 750 mm wide giving access to the interior.	AD M Vol 2 §15.3
M4(2) and M4(3) are optional	They apply only where the local planning authority has imposed them as a planning condition. M4(1) is the default for all new dwellings.	Building Regulations 2010, reg. 36A

Overheating

2021 edition

O1 · Overheating mitigationReasonable provision must be made in respect of a dwelling, institution or any other building containing one or more rooms for residential purposes (other than a hotel) to limit unwanted solar gains in summer, and provide an adequate means to remove heat from the indoor environment.

Topic	The rule — exact figures	Source
Scope	Applies to new residential buildings only — dwellings, institutions, and buildings containing rooms for residential purposes, but not hotels.	Requirement O1
Two compliance routes	The simplified method (maximum glazing areas and minimum free areas by risk location and cross-ventilation) or dynamic thermal modelling to CIBSE TM59.	AD O §1.2
Moderate-risk, cross-ventilated	Maximum glazing area the greater of 9% of floor area or 55% of the glazing area free area; bedroom minimum free area 4% of floor area.	AD O Table 1.1
High-risk locations	Maximum glazing and minimum free areas tighten to 6%/70% and 12%/80% bands, with bedroom free area up to 13% of floor area. High-risk = parts of central London; central Manchester (M1, M2, M3, M5, M15, M16, M50) should also be considered.	AD O Table 1.1, Appendix C
Room depth for assessment	Where a room serves more than one activity, assess the area with the largest glazing and calculate the room area on a depth no greater than 4.5 m from the glazed façade.	AD O Appendix A
Noise limits at night	Where openings are the removal strategy, night-time noise should not exceed 40 dB LAeq,T averaged over 8 hours (23:00–07:00) and 55 dB LAFmax more than 10 times a night.	AD O §3.x
Openings wider than 100 mm	Permitted as part of the strategy only where the stated security and safety conditions are met.	AD O §3.9
Guarding at openings	Guarding height 1.1 m where the change in level is more than 600 mm; guarding sized to prevent the passage of a 100 mm sphere.	AD O Table 3.1
Finger entrapment	Any hole which allows the passage of an 8 mm diameter rod should also allow the passage of a 25 mm diameter rod, and must not taper so as to trap fingers.	AD O §3.x
Window handle reach	On outward-opening windows, handles not more than 650 mm from the inside face of the wall at maximum opening angle.	AD O §3.x
Automated openings	Start to open above 22°C, fully open above 26°C, start to close below 26°C, fully closed below 22°C.	AD O §3.x
Information	Details of the overheating strategy must be given to the owner.	Building Regulations 2010, reg. 40B

Electrical safety — dwellings

2013 edition

P1 · Design and installationReasonable provision shall be made in the design and installation of electrical installations in order to protect persons operating, maintaining or altering the installations from fire or injury.

Topic	The rule — exact figures	Source
Technical standard	BS 7671 (the IET Wiring Regulations) is the standard referenced by Approved Document P.	AD P §1.1
Notifiable work	Only three categories: (a) installation of a new circuit; (b) replacement of a consumer unit; (c) any addition or alteration to existing circuits in a special location.	Building Regulations 2010, reg. 12(6A)
Special location — vertical extent	In a room containing a bath or shower: from finished floor level to 2.25 m, or to the shower head position where that is higher than 2.25 m.	reg. 12(9)(a)(i)
Special location — horizontal extent	0.6 m from the edge of the bath tub or shower tray; or where there is no tub or tray, 1.2 m from the centre point of the shower head where it is attached to the wall or ceiling.	reg. 12(9)(a)(ii)
Special location — other	A room containing a swimming pool or sauna heater.	reg. 12(9)(b)
Socket outlets near a bath	Socket outlets should not be located within 3 m of a bath tub or shower tray.	AD P Diagram 2 note
Certification routes	Notifiable work may be certified by a registered competent person, by a registered third party certifier, or through a building control body.	AD P §1.x
Non-notifiable work	Replacements, repairs and maintenance anywhere, and additions/alterations to existing circuits outside a special location, are not notifiable — but must still comply with BS 7671.	AD P §2.x

Security — dwellings

2015 edition

Q1 · Unauthorised accessReasonable provision must be made to resist unauthorised access to any dwelling, and any part of a building from which access can be gained to a flat within the building.

Topic	The rule — exact figures	Source
Scope	Applies to new dwellings only, including those formed by a material change of use. Not to extensions or replacement doors and windows in an existing dwelling.	AD Q §0.x
Doorsets	Easily accessible doorsets must be secure, tested to PAS 24 or equivalent (STS 201, LPS 1175 Issue 7 Security Rating 2, or Secured by Design).	AD Q §1.1–1.2
Which doors count	Any door providing access into the dwelling from outside, from a communal area, or from an integral garage; and easily accessible windows.	AD Q §1.1
Glazing in doors	Where a door has glazing that could allow entry, it should be laminated glass to BS EN 356 or the equivalent tested doorset performance.	AD Q §1.x
Letter plates	Maximum aperture 260 × 40 mm, with a letter plate design that resists arm entry or fishing.	AD Q §1.x
Windows	Easily accessible windows should be secure to PAS 24 or equivalent — those in a ground-floor, basement or other easily accessible position.	AD Q §2.1
Framing	Frames must be mechanically fixed to the structure in accordance with the manufacturer's installation instructions.	AD Q §1.x

Physical infrastructure for high-speed electronic communications networks

2016 edition, 2022 amendments

R1 · In-building physical infrastructureBuilding work must be carried out so as to ensure that the building is equipped with a high-speed-ready in-building physical infrastructure, up to a network termination point for high-speed electronic communications networks.

RA2 · Gigabit-ready physical infrastructure and connectionWhere a new dwelling is erected, it must be equipped with gigabit-ready physical infrastructure and, except where exemptions apply, connected to a gigabit-capable public electronic communications network.

Topic	The rule — exact figures	Source
Scope	New buildings and buildings undergoing major renovation works (works affecting the in-building physical infrastructure).	Requirement R1
Gigabit connection duty	A new dwelling must be connected to a gigabit-capable network where a connection can be secured within a cost cap of £2,000 per dwelling.	reg. 44ZA / AD R Part 2
If the cap is exceeded	Connect to the next-fastest network that can be secured within the cost cap; if none, install gigabit-ready physical infrastructure only.	AD R Part 2
Exemptions	Buildings exempt from Part R include certain listed buildings, temporary buildings, standalone buildings under 50 m² and some agricultural buildings.	AD R §0.x
Evidence	The developer must keep evidence of the steps taken to secure a connection where the cost cap is relied on.	AD R Part 2

Infrastructure for the charging of electric vehicles

2021 edition

S1 · New residential buildingsWhere a new residential building has associated parking spaces, each dwelling with an associated parking space must have access to an electric vehicle charge point.

S2 · Residential buildings undergoing major renovationWhere a residential building undergoing major renovation will have more than 10 associated parking spaces, each dwelling with an associated parking space must have access to a charge point, and cable routes must be installed in all remaining spaces.

S3 · New buildings other than residentialWhere a new building other than a residential building has more than 10 associated parking spaces, at least one charge point must be installed and cable routes installed in a minimum of one fifth of the remaining spaces.

S4 · Buildings other than residential undergoing major renovationAs S3, applied to buildings undergoing major renovation with more than 10 associated parking spaces.

S5/S6 · Mixed-use buildings and informationMixed-use buildings are treated according to their parts, and information about the charge point installation must be provided.

Topic	The rule — exact figures	Source
Major renovation definition	Renovation of a building where more than 25% of the surface area of the building envelope undergoes renovation.	AD S, key terms
The 7% cost cap	Where the cost of installing the required charge points and cable routes exceeds 7% of the total cost of the major renovation, the requirement steps down — first to cable routes only, then to nothing if that too exceeds 7%.	regs. 44H–44L / AD S §4.x
Covered car parks	In a covered car park, the requirement applies in all parking spaces where there are more than 10 parking spaces.	AD S §3.x
Wall-mounted charge point space	Charge point mounted 700–1000 mm above floor; free space at least 800 × 800 mm, with ≥500 mm and ≥200/400 mm clearances to walls and objects.	AD S Diagram 6.4
Floor-mounted charge point space	Free space at least 1500 × 1500 mm, with clearances of ≥220 mm, ≥1200 mm, ≥500 mm and ≥450 mm as shown.	AD S Diagram 6.4
Accessible parking bay	Bay 2.4 m wide with 1.2 m access zones each side and to the rear, giving 4.8 m overall, derived from BS 8300-1 and AD M Vol 2.	AD S Diagram 6.1
Signage	The charge point sign should measure 506 × 194 mm, each letter 25 mm high, text displayed over three lines.	AD S §6.x
Vehicle barrier allowance	Where vehicle barriers will be needed for a future charge point, allow sufficient space — for example 500 mm — around the future connection location.	AD S §6.x

About this reference. Compiled from the merged Approved Documents, the Manual to the Building Regulations, the Building Regulations 2010 as amended, the Building Act 1984 and the Building Safety Act 2022. England only; Wales, Scotland and Northern Ireland have separate regimes. Approved Documents are statutory guidance, not the law — compliance is judged against Schedule 1. Editions change: verify against gov.uk before relying on any figure contractually. Last reviewed 17 August 2026. Not a substitute for a building control body, a structural engineer or a fire engineer.