They are two different approvals, and people mix them up all the time. Planning is about how the work looks and fits in. Building control is about whether it’s safe to live in.
What it checks
- Planning permission
- How it looks and fits in: size, height, materials, windows, the effect on neighbours
- Building regulations (building control)
- Whether it’s safe and sound: structure, fire safety, ventilation, damp, insulation, drains
Who decides
- Planning permission
- The council’s planning department
- Building regulations (building control)
- The council’s building control, or a registered building control approver
When you need it
- Planning permission
- When the work is outside permitted development (flats have none)
- Building regulations (building control)
- For most building work: extensions, loft conversions, taking out a structural wall
How long
- Planning permission
- Up to 8 weeks for a householder application
- Building regulations (building control)
- Full plans: within 5 weeks, or 2 months if you agree
What you get
- Planning permission
- A decision notice
- Building regulations (building control)
- Plans approval, inspections as the work goes, then a completion certificate
| Planning permission | Building regulations (building control) | |
|---|---|---|
| What it checks | How it looks and fits in: size, height, materials, windows, the effect on neighbours | Whether it’s safe and sound: structure, fire safety, ventilation, damp, insulation, drains |
| Who decides | The council’s planning department | The council’s building control, or a registered building control approver |
| When you need it | When the work is outside permitted development (flats have none) | For most building work: extensions, loft conversions, taking out a structural wall |
| How long | Up to 8 weeks for a householder application | Full plans: within 5 weeks, or 2 months if you agree |
| What you get | A decision notice | Plans approval, inspections as the work goes, then a completion certificate |
Do I need both?
Often, yes. An extension within permitted development needs no planning application, but it still needs building regulations approval. One never covers the other.
An example: a 5 m single-storey rear extension
- 1Check what’s on the landA listed building, a conservation area or an article 4 direction changes the rules. Check this first.
- 2PlanningIn England, on a house that isn’t detached, 3 m is allowed without an application. Up to 6 m needs the council’s prior approval. Further than that needs a householder planning application.
- 3A structural engineerCalculations for the new foundations and the beam over the new opening, and a check on any wall that’s coming out.
- 4Building regulation drawingsHow it meets the rules on structure, fire safety, ventilation, damp and insulation.
- 5Building controlA full plans application to the council or a registered approver, then inspections as the work goes, and a completion certificate at the end.
Keep these
- The planning decision notice, or the prior approval letter
- The building regulations plans approval
- The completion certificate: you’ll need it when you sell
What would your job cost?
Describe it, and see a typical price for your area. Then ask builders who do this work.
Read next
How we wrote this
Written by Structa. The rules come from the official pages below. General information, not legal advice.
- GOV.UK: Planning permission (checked 6 October 2026)
- The Town and Country Planning (Development Management Procedure) (England) Order 2015, article 34: eight weeks to decide (checked 16 October 2026)
- GOV.UK: Building regulations approval (checked 6 October 2026)
- Planning Portal: full plans (a decision within five weeks, or two months if you agree) (checked 16 October 2026)
- GOV.UK: Permitted development rights for householders, technical guidance (checked 16 October 2026)