Building Regulations: The Complete Guide for Homeowners

These are two separate systems run by different people for different reasons.

Planning permission controls what you build and where — the size, position, appearance, and impact on your neighbours and surroundings. It is decided by your council’s planning department.

Building regulations control how you build — the structure, fire safety, insulation, drainage, electrics, and ventilation. They are checked by building control (either your council or a private approved inspector).

You can get planning permission for an extension but still fail building regulations if the construction is not up to standard. And you can build something that meets building regulations perfectly but still need planning permission for it.

Read our detailed comparison →

Building regulations are organised into “Approved Documents” — each covering a different aspect of construction. The ones that matter most for typical home projects are:

For a typical rear extension, Parts A, B, C, F, K, L, and P are the ones you will encounter most.

Projects that need building regulations:

• Extensions (all types — rear, side, wraparound, two-storey)
• Loft conversions
• Garage conversions
• Removing or altering a loadbearing wall
• New or replacement heating system (boiler, heat pump)
• Electrical work in kitchens, bathrooms, outdoors, or involving new circuits
• Replacement windows and doors (must meet thermal and safety standards)
• Re-roofing (if more than 25% of the roof area)
• Adding a bathroom or WC
• Underpinning
• Changes to drainage (foul or surface water)

Projects that usually do NOT need building regulations:

• Small detached outbuildings under 15m² with no sleeping accommodation
• Detached outbuildings 15–30m² (with conditions — no sleeping, 1m+ from boundary)
• Porches under 30m² that are at ground level and separated from the house by an external door
• Conservatories under 30m² at ground level, separated from the house by external walls/doors, with an independent heating system
• Like-for-like repairs (replacing a rotten joist with an identical one, for example)
• Decorating, minor repairs, and maintenance
• Garden walls, fences, and gates (under 1.8m)

The grey areas:

Replacement windows: If installed by a FENSA-registered installer (or equivalent competent person scheme), the installer self-certifies compliance and you do not need a separate building regulations application. If installed by a non-registered installer, you must apply for building regulations approval separately.

Electrical work: Minor electrical work (like replacing a socket or light fitting) does not need building regulations. But new circuits, work in kitchens and bathrooms, and outdoor electrical installations do. If the work is done by a Part P registered electrician, they self-certify. Otherwise, you need building regulations approval.

There are two ways to get building regulations approval. Both are valid and result in the same completion certificate.

Building Notice

You submit a short form (usually 2 pages) and pay the fee. You can start work 48 hours after submitting the notice. Building control reviews the work as it progresses through site inspections.

Pros:

• Quick to submit — you can start work almost immediately
• Less paperwork upfront
• Lower initial cost (no detailed drawings needed)

Cons:

• No approved plans before work starts — building control may require changes mid-build
• Your builder carries more risk
• If anything is wrong, it may need to be redone

Best for straightforward projects where the builder knows the building regulations requirements well — simple extensions, window replacements, boiler installations.

Full Plans

You submit detailed architectural and structural drawings showing exactly what will be built and how it complies with the regulations. Building control checks the drawings and issues a decision (approve, approve with conditions, or reject) within 5 weeks (or 2 months if you agree to an extension).

Pros:

• You know the design is approved before work starts
• Less risk of costly changes during construction
• Provides a formal record of what was approved

Cons:

• Takes longer to start (you need detailed drawings first)
• Slightly higher cost (drawings + submission fee)
• Building control may request amendments to the drawings

Best for larger or more complex projects — loft conversions, structural alterations, projects where you want certainty before committing to a build contract.

1. Choose your building control provider

You have two options:

Local authority building control (LABC): Your council’s in-house service. You apply through your council’s website or the LABC portal.

Private approved inspector: A private company registered with the Building Safety Regulator. You contract with them directly. They have the same legal powers as local authority building control.

The choice is yours. Private inspectors are sometimes faster and more flexible. Local authority building control is sometimes cheaper and offers continuity with your planning department. Both issue the same completion certificate.

2. Submit your application

• Building Notice route: Submit the form with basic project details and the fee. You can start work after 48 hours.
• Full Plans route: Submit detailed drawings with the fee. Wait for a formal decision (up to 5 weeks).

3. Site inspections

Building control will inspect the work at key stages. You (or your builder) must notify them before covering up work that needs inspecting. The typical stages are:

If an inspector finds something that does not comply, they will tell you (or your builder) what needs to be changed. It is much better to get this right during the build than to have to undo finished work.

4. Completion certificate

When the work passes the final inspection, building control issues a completion certificate. This is the official document confirming that the work complies with building regulations.

Keep this certificate. You will need it when you sell the property. Your buyer’s solicitor will ask for it, and not having one creates problems and delays.

Fees vary by council and by project type. Typical ranges for 2026:

These fees typically cover the plan check (for Full Plans applications) and all site inspections. Some councils charge a single fee; others split it into a “plan fee” and an “inspection fee.”

Private approved inspectors set their own fees, which may be higher or lower than the local authority.

If you carry out work that needed building regulations approval without getting it, you are breaking the law. But the consequences are practical rather than criminal in most cases.

The enforcement power:

Your local authority can serve an enforcement notice requiring you to alter or remove work that does not comply with building regulations. They must do this within 12 months of the work being completed (Section 36 of the Building Act 1984). After 12 months, they lose the right to require removal — but that does not mean the work is approved.

The real-world consequences:

• Selling your property: Your buyer’s solicitor will ask for completion certificates. No certificate means the sale can be delayed or the buyer may reduce their offer.
• Mortgage and insurance: Some mortgage lenders require completion certificates. Building insurance may not cover work done without building regulations.
• Safety: Building regulations exist for good reasons. Work done without proper inspection may have structural, fire safety, or electrical problems that are not visible.

Retrospective regularisation:

If work was done without building regulations approval and the 12-month enforcement window has passed, you can apply for a regularisation certificate. Building control will inspect the work (which may mean opening up walls or floors) and confirm whether it complies. If it does not, they will tell you what needs to be fixed.

Regularisation fees are typically higher than standard fees — often 50–100% more — because building control cannot inspect the work at each stage.

Read more about building without permission →

1. Confusing building regulations with planning permission. Getting planning permission (or building under permitted development) does not mean your building work complies with building regulations. They are two separate systems and you may need both. Read our comparison →

2. Starting work before notifying building control. Even with a Building Notice, you must submit it 48 hours before starting. Starting without notifying building control can result in them not accepting responsibility for inspecting the work.

3. Covering up work before inspection. If you pour concrete over foundations before building control has inspected them, they may require you to expose them again — at your cost.

4. Not getting a completion certificate. When the work is finished, make sure building control issues the completion certificate. Chase them if necessary. Without it, you will have problems when you sell.

5. Assuming “competent person” work does not need certificates. When a FENSA window installer or Gas Safe engineer self-certifies, they should send notification to your local authority and you should receive a certificate. If you do not receive one, follow up. You need these certificates when you sell.

Certain types of work can be “self-certified” by tradespeople who are registered with an approved competent person scheme. This means you do not need a separate building regulations application — the tradesperson certifies that the work complies.

When using a competent person scheme, the installer notifies your local authority directly and you receive a certificate. Always check that your tradesperson is actually registered before assuming they can self-certify.

You have two options for building control approval:

Local Authority Building Control (LABC): Your council’s in-house service. Find your local LABC team using the postcode finder at labc.co.uk.

Private Approved Inspector: A private company registered with the Building Safety Regulator. You contract with them directly. Find a registered inspector at cicair.org.uk.

Both routes have the same legal authority and issue the same completion certificate. The choice comes down to cost, availability, and which suits your project better.

1. Check whether your project needs building regulations — use the list above or contact your local building control team
2. Decide between Building Notice and Full Plans based on your project’s complexity
3. If your project also needs planning permission, check your property using our free PD checker
4. Read our building regulations vs planning permission guide to understand how the two systems interact