Building Regulations vs Planning Permission: What's The Difference?
Planning permission and building regulations approval are separate legal requirements. You may need one, both or neither depending on the project — but confusing them is one of the most common homeowner mistakes.
Published: June 2025 · Last reviewed: 24 June 2025
The 10-second answer
What is planning permission?
Approval for whether development is acceptable in planning terms. See planning permission explained.
What are building regulations?
Approval that building work meets standards for structure, fire safety, insulation, drainage and accessibility.
Can I need both?
Yes — very often for extensions, loft conversions and garage conversions.
Does this apply in Scotland?
Scotland uses building warrants instead — see building warrant vs planning permission.
Which route might apply?
Planning: permitted development may apply if:
- The project falls within permitted development limits.
- The property retains those rights.
This does not automatically mean permitted development applies. Every property and proposal is different and still needs to be checked.
Planning permission may be needed if:
- The project exceeds permitted development or the property is restricted.
Many projects require planning permission, but the answer depends on the individual circumstances.
See planning permission vs permitted development for the wider planning overview. If your property is in Scotland, see building warrant vs planning permission instead.
What is planning permission?
Planning permission addresses whether development is acceptable in land-use and amenity terms — impact on neighbours, character, highways and policy. See planning permission explained.
What are building regulations?
Building regulations in England and Wales set technical standards for construction: structural stability, fire safety, ventilation, thermal efficiency, drainage and more. Approval is usually obtained through a building control body (the council or an approved inspector).
Building regulations do not judge whether your extension should be built — they judge whether it is built safely and to standard.
When homeowners need both
Common projects needing both planning permission (or permitted development) and building regulations:
- Extensions — see extension planning permission guide; extension costs guide
- Loft conversions — see loft conversion planning permission; loft conversion costs guide
- Garage conversions — see garage conversion planning permission
- Structural alterations and removals of walls
- New windows in new openings (building regulations; planning may also apply)
Typical homeowner examples
These examples illustrate common situations. They are not formal determinations and do not guarantee an outcome.
Rear extension with permitted development
No planning application needed if permitted development applies — but building regulations approval is still required. See rear extension planning permission.
Loft conversion
May not need planning permission — but building regulations cover stairs, fire escape and structure. See loft conversion planning permission.
Internal remodel only
May not need planning permission if no external changes — but building regulations may apply to structural work.
How to check your property
Before relying on general guidance, check the property and proposal together.
- Check the planning route first. See planning permission vs permitted development.
- Check building regulations requirements. Contact building control or your contractor.
- Submit building regulations application or notice. Before work starts in most cases.
- Arrange inspections during construction. Building control inspects at key stages.
- Obtain completion certificate. Important for selling the property.
Plimbu helps bring these checks together so you can understand the likely planning route before going further.
Common mistakes
- Assuming planning permission covers building standards.
- Starting work without building control involvement.
- Not obtaining a completion certificate when selling.
- Confusing England's building regulations with Scotland's building warrant — see building warrant vs planning permission.
Frequently asked questions
Do garden rooms need building regulations?
Habitable garden buildings often do. Small non-habitable sheds may not.
Who approves building regulations?
The local council's building control team or a private approved inspector.
How much do building regulations cost?
Fees vary by project size and whether you use council or private building control. Include in the extension costs guide or loft conversion costs guide.
Can I get building regulations approval without planning permission?
Yes — they are independent. But you still need lawful planning status.
Check planning requirements for your project
Plimbu helps with the planning route. Remember to arrange building regulations approval separately.
This guide is general information, not formal planning advice. For property-specific checks, start with your postcode in Plimbu.