What is the difference between building regulations and planning permission?

Building regulations ensure construction is safe and energy efficient. Planning permission controls how land and buildings are used. You may need both, one, or neither depending on your project. A loft conversion typically needs building regulations but may not need planning if within permitted development.

What happens if I do work without building regulations approval?

You risk enforcement action requiring you to demolish or undo work. When selling, buyers and solicitors check for completion certificates. Missing certificates can delay sales, reduce value, or require expensive regularisation applications.

How much does building regulations approval cost?

Full plans applications typically cost £250 to £800 depending on project size and local authority. Building notice is usually 10% to 20% cheaper. Competent person scheme work is self certified at no additional council fee.

Do I need building regulations for a new bathroom?

Usually not for like for like replacement. Building regulations apply if you are adding new electrical circuits, significantly moving waste pipes, or creating a new bathroom in a location that did not have one.

Building Regulations Explained UK: Complete Guide 2025

When You Need Approval and How to Get It

10 min read

~2,300 words

Updated December 2025

£250 to £800

Typical Application Cost

5 weeks

Average Approval Time

14 Parts

Approved Documents

Building regulations ensure that construction work is safe, energy efficient, and accessible. Unlike planning permission (which controls appearance and land use), building regulations focus on how something is built, not whether you can build it.

Many homeowners are confused about when building regulations apply. This guide clarifies which projects need approval, how to apply, and what happens if you skip the process.

Building Regulations vs Planning Permission

Building Regulations

Focus on safety and quality
Technical construction standards
Checked by Building Control
You get a Completion Certificate

Planning Permission

Focus on appearance and use
Impact on neighbours and area
Decided by Planning Department
You get a Decision Notice

Which Projects Need Approval?

Quick reference guide for common home improvement projects.

Project	Building Regs	Planning	Notes
Loft conversion	Required	Depends	Building regs always required. Planning only if extending roof or in conservation area.
Kitchen renovation	Depends	Not Required	Only if structural, electrical (new circuits), or moving gas. Cosmetic work exempt.
Bathroom renovation	Depends	Not Required	Only if new electrical circuits or moving waste pipes significantly.
Knocking through walls	Required	Not Required	Always required for structural walls. May need engineer's calculations.
Single storey extension	Required	Depends	Building regs always. Planning depends on size and location (PD rights).
Electrical work (new circuits)	Required	Not Required	Part P applies. Must be done by registered electrician or notified to Building Control.
Gas boiler installation	Required	Not Required	Must be Gas Safe registered installer. They self certify.
Replacing windows	Required	Depends	FENSA registered installer self certifies. Planning if listed or conservation.
Rewiring whole house	Required	Not Required	Part P applies. Registered electrician or Building Control notification.
New central heating	Required	Not Required	Gas Safe installer self certifies. Oil and renewable may need planning.
Internal walls (non structural)	Not Required	Not Required	Generally exempt unless fire regulations affected.
Decorating and flooring	Not Required	Not Required	Completely exempt. No approval needed.

The Approved Documents

Building regulations are divided into "parts" covering different aspects. These are the most relevant for home renovations.

Part AStructure

Structural stability, foundations, walls, roofs

Relevant for: Extensions, loft conversions, removing walls, underpinning

Part BFire Safety

Escape routes, fire doors, smoke alarms, fire spread

Relevant for: Loft conversions, open plan alterations, HMOs

Part ESound

Sound insulation between dwellings

Relevant for: Flat conversions, party wall work, loft rooms

Part FVentilation

Air quality, extraction, background ventilation

Relevant for: Bathrooms, kitchens, extensions, replacement windows

Part GSanitation

Hot water safety, bathrooms, drainage

Relevant for: Bathroom additions, drainage changes, water systems

Part LEnergy Efficiency

Insulation, heating efficiency, thermal elements

Relevant for: Extensions, windows, heating, insulation upgrades

Part PElectrical Safety

Electrical installations in dwellings

Relevant for: New circuits, bathroom electrics, outdoor wiring, consumer units

How to Get Approval

Three routes to compliance, each suited to different projects.

Full Plans Application

Submit detailed plans before work starts. Building Control reviews and approves.

Timeline

5 weeks typical (up to 2 months)

Cost

£250 to £800 depending on project and authority

Best For

Complex projects, extensions, loft conversions, structural work

Pros

Certainty before starting, plans approved, clear record

Cons

Upfront cost, waiting time, may need architect

Building Notice

Give 48 hours notice before starting. Inspector visits during work.

Timeline

48 hours notice, inspections during work

Cost

£200 to £600

Best For

Simpler projects where you are confident of compliance

Pros

Faster start, lower cost, less paperwork

Cons

No upfront approval, risk of changes required mid project

Competent Person Scheme

Registered tradesperson self certifies their work. No council involvement.

Timeline

Immediate on completion

Cost

Included in installer price

Best For

Electrical, gas, windows, heating by qualified installers

Pros

No council fees, faster, simpler

Cons

Must use registered installer, limited to their work scope

What If You Skip Building Regulations?

Real Consequences

Enforcement action: Council can require you to undo or demolish non compliant work, even years later.
Sale problems: Solicitors check for completion certificates. Missing documents delay or block sales.
Reduced value: Buyers negotiate discounts or require indemnity insurance for uncertified work.
Insurance issues: Home insurance may not cover damage from non compliant construction.
Safety risks: Regulations exist for good reasons. Non compliant work can be genuinely dangerous.

Key Takeaways

Building regs ensure safety and efficiency. Planning controls appearance and use.

Electrical work, gas work, structural changes always need approval.

Use Competent Person Scheme installers when possible to avoid council fees.

Keep completion certificates. Essential when selling your property.

Work without approval can block house sales and require demolition.

Full plans cost more but give certainty before you start work.

Plan Your Project Budget

Include Building Control fees in your renovation budget with our free calculator.

Use Cost Calculator

Related Guides

Do I Need Planning Permission?

Complete guide to planning permission requirements.

Loft Conversion Guide UK

Everything about loft conversions including regulations.

How to Vet a UK Contractor

Ensure your contractor understands regulations.

Kitchen Renovation Costs UK

When kitchen work needs building control.

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