Building regulations and planning permission are two separate systems that often get confused. While planning controls what you can build and where, building regulations control how you build - ensuring structures are safe, energy efficient, and accessible.
When Do Building Regulations Apply?
Most building work requires building regulations approval, including:
- Extensions and conversions
- Structural alterations (removing walls, adding beams)
- New or replacement heating systems
- Electrical work in kitchens, bathrooms, and outdoors
- Replacement windows (unless installed by a FENSA-registered company)
- New bathrooms or kitchens (if involving drainage changes)
- Underpinning
Exempt Work
Some minor work doesn't need building regulations:
- Like-for-like repairs
- Detached buildings under 15m² with no sleeping accommodation
- Certain porches under 30m²
- Some conservatories (if thermally separated from the house)
The Two Routes
Full Plans Application
Submit detailed plans before you start. Building control checks them and issues an approval notice. Best for complex work where you want certainty upfront.
Building Notice
Notify building control that you're starting work - no plans required. Quicker and cheaper, but riskier: if inspectors find problems during construction, you may need to redo work.
Local Authority vs Approved Inspectors
You can use either your council's building control team or a private Approved Inspector. Private inspectors often offer faster response times and more flexible inspection scheduling, while council building control has the advantage of local knowledge and no profit motive.
The Inspection Process
Typical inspection stages for an extension:
- Commencement - notify before you start
- Foundation excavation - before concrete is poured
- Foundation concrete - before backfilling
- Damp-proof course
- Drainage - before covering
- Structural frame / floor / roof - before covering
- Insulation - before plasterboarding
- Completion - final inspection
The Completion Certificate
When work is finished and inspected, building control issues a completion certificate. This is a crucial document:
- Required by mortgage lenders and conveyancers
- Proves the work meets building regulations
- Needed if you sell the property
- Without it, you may need retrospective regularisation (which costs more and involves opening up completed work)
Always get your completion certificate. It's one of the most commonly missed steps in home improvement projects.