Mortgages & PropertyBuilding 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.
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 |
Useful Links
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