What are Building Regulations?

Building Regulations are minimum standards for the design, construction, and alteration of buildings in England and Wales, set out in the Building Act 1984 and detailed in Approved Documents A–S. They cover structural safety, fire safety, energy efficiency, ventilation, drainage, electrical safety, accessibility, and more. Most building work requires Building Regulations approval — this is separate from planning permission. Scotland has its own Building Standards, and Northern Ireland has its own Building Regulations.

Do I need Building Regulations approval?

Most building work needs Building Regulations approval, including extensions, loft conversions, structural alterations, new heating systems, electrical work (in bathrooms and kitchens), replacement windows, new bathrooms, garage conversions, and underpinning. Some minor work is exempt — like small detached buildings (under 15m²), some repairs, and replacements using competent person scheme installers. Even if planning permission isn't needed, Building Regulations almost always are.

What's the difference between Building Regulations and planning permission?

Planning permission controls WHAT you can build and WHERE (appearance, size, location, impact on neighbours). Building Regulations control HOW it's built (structural safety, fire safety, energy efficiency, drainage, etc.). You may need one, both, or neither depending on the project. For example, a small extension may not need planning permission (permitted development) but will absolutely need Building Regulations. A change of use may need planning permission but minimal Building Regs work.

What happens if I don't get Building Regulations approval?

If you carry out work without required Building Regulations approval, your local authority can issue an enforcement notice requiring you to alter or remove the work. They can also prosecute — fines are unlimited. When you sell your property, the buyer's solicitor will check for Building Regulations completion certificates. Missing certificates can delay or derail a sale, reduce the property value, or require you to buy indemnity insurance. Some mortgage lenders won't lend on properties with unapproved work.

Building Regulations Guide UK — What You Need to Know | PocketWise

Building Regulations Guide UK — What You Need to Know

What Building Regulations are, when you need approval, how to apply, common projects that require Building Regs, and the penalties for non-compliance.

By PocketWise · 25 March 2026 · 5 min read

Building Regulations ensure building work is safe, energy-efficient, and structurally sound. Here’s when you need approval and how to get it.

Building Regulations vs Planning Permission

Feature	Building Regulations	Planning Permission
What it controls	HOW you build — safety, structure, energy, drainage	WHAT and WHERE — appearance, size, impact
Who enforces	Local authority Building Control or approved inspectors	Local planning authority
When needed	Nearly all building work	Depends on size, location, type of work
Application fee	Varies (see below)	Varies (see planning permission guide)
Certificate	Completion certificate	Planning approval notice
Penalty for non-compliance	Enforcement notice, prosecution, fines	Enforcement notice, demolition order

What the Building Regulations Cover

Approved Document	Subject
Part A	Structure (foundations, walls, loading)
Part B	Fire safety (escape routes, fire spread, access for fire services)
Part C	Site preparation and resistance to contaminants and moisture
Part D	Toxic substances
Part E	Resistance to sound (soundproofing between dwellings)
Part F	Ventilation
Part G	Sanitation, hot water safety, water efficiency
Part H	Drainage and waste disposal
Part J	Combustion appliances and fuel storage
Part K	Protection from falling (stairs, ramps, guards)
Part L	Conservation of fuel and power (energy efficiency)
Part M	Access to and use of buildings (accessibility)
Part O	Overheating (new builds and some extensions)
Part P	Electrical safety (dwellings)
Part Q	Security (new dwellings — doors and windows)
Part R	Physical infrastructure for high-speed electronic communications
Part S	Infrastructure for charging electric vehicles

Projects That Need Building Regulations

Project	Building Regs needed?	Key parts
Extension	Yes	A, B, E, F, G, H, J, K, L, M, P
Loft conversion	Yes	A, B, F, K, L, P
Garage conversion	Yes	A, B, F, L, P
Structural alterations (removing walls)	Yes	A
New boiler/heating system	Yes (or competent person scheme)	J, L
Replacement windows/doors	Yes (or FENSA/competent person)	L, N, Q
Electrical work (bathrooms, kitchens, new circuits)	Yes (or competent person — Part P)	P
New bathroom/WC	Yes	G, H, F, P
Re-roofing	Yes (if more than 25% of the area)	L
Underpinning	Yes	A
Basement conversion	Yes	A, B, C, F, K, L, M
Solar panels	Usually not (if on-roof)	May need if structural
New build	Yes — everything	All parts

Work That Usually Doesn’t Need Building Regulations

Work	Condition
Like-for-like repairs	Replacing materials with the same specification
Small detached buildings	Under 15m² with no sleeping accommodation
Porches	Under 30m², single storey, at ground level
Conservatories	Under 30m², at ground level, separated from the house by an external-quality wall/door, with independent heating controls
Carports	Open on at least two sides, under 30m²
Garden walls, fences, gates	Under certain heights
Internal decorating	No structural changes
External painting	No change to materials/structure

How to Apply

Two Routes

Route	Detail
Local authority Building Control	Your council’s Building Control department
Approved Inspector	A private sector alternative (must be registered with CICAIR)

Application Types

Type	When	How it works
Full plans application	Major work (extensions, conversions, structural)	Submit detailed plans → Building Control checks → approve with/without conditions → inspect during work → completion certificate
Building notice	Smaller work (where plans aren’t needed)	Notify Building Control 48 hours before starting → they inspect during work → completion certificate
Regularisation	Work already done without approval	Apply retrospectively → Building Control inspects → may require opening up work for inspection → regularisation certificate (if compliant)

Fees (Approximate)

Project	Building Control fee (approx.)
Small extension (up to 40m²)	£400–£800
Medium extension (40–80m²)	£600–£1,200
Loft conversion	£400–£900
Garage conversion	£300–£600
Structural alterations	£200–£500
Electrical work (full plans)	£200–£400
New dwelling	£1,000–£3,000
Regularisation application	+25–50% on top of the standard fee

Fees vary by council.

Competent Person Schemes

Scheme	Trades	What it means
Gas Safe	Gas boilers, heating	Installer self-certifies compliance — no separate Building Regs application needed
FENSA/CERTASS	Replacement windows and doors	Self-certification for Part L compliance
NICEIC/NAPIT/ELECSA	Electrical work	Self-certification for Part P compliance
HETAS	Solid fuel stoves and installations	Self-certification
OFTEC	Oil heating	Self-certification
MCS	Renewable energy (solar, heat pumps)	Self-certification

Key: If your installer is registered with a competent person scheme, they can self-certify the work and notify Building Control on your behalf — saving you the application fee and hassle.

Inspections

Stage	When
Commencement	When work starts (or foundations are dug)
Foundations	Before concrete is poured
Damp-proof course	Before walls are built above DPC level
Drainage	Before trenches are filled
Structural work	Before covering steels, beams, etc.
Pre-plaster	Before walls are plastered (insulation, fire stopping, ventilation)
Completion	Final inspection before occupation/use

Completion Certificates

Feature	Detail
What it is	Official confirmation that the work complies with Building Regulations
Who issues it	Local authority Building Control or the approved inspector
When you get it	After the final inspection and any issues are resolved
Why it matters	Required for property sales, mortgage applications, and insurance
Keep it safe	You’ll need it when you sell your property
Missing certificate?	Apply for a regularisation certificate — or buy indemnity insurance

Penalties for Non-Compliance

Penalty	Detail
Enforcement notice	Council orders you to alter or remove non-compliant work
Prosecution	Council can prosecute — fines are unlimited
Property sale problems	Buyer’s solicitor will spot missing certificates — can delay or collapse a sale
Insurance issues	Some insurers won’t cover unapproved work
Mortgage problems	Lenders may refuse to lend on properties with unapproved work
Safety risk	Non-compliant work may be structurally unsafe, a fire risk, or energy-inefficient

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