Planning permission is one of those things that sounds straightforward until you actually try to figure out whether you need it. The short answer: it depends. The slightly longer answer: your local planning authority (LPA) has to approve certain types of development before you can build. But loads of common projects fall under “permitted development rights” and don’t need a formal application at all. Get it wrong, though, and you could face enforcement action, fines, or being told to demolish something you’ve already built. Not fun.
Permitted Development Rights
Permitted development (PD) lets you do certain types of work without a planning application. For houses (not flats or maisonettes), these include:
- Single-storey rear extensions: Up to 4 metres from the original rear wall (detached houses) or 3 metres (everything else). Under the larger home extension scheme, you can go up to 8m and 6m respectively — but you need to submit a prior approval notification to the LPA and your neighbours get consulted.
- Loft conversions: Up to 40 cubic metres extra roof space (terraced) or 50 cubic metres (detached and semis), provided dormers don’t face a highway and you don’t go above the existing ridge line.
- Outbuildings: Garden offices, sheds, summer houses, even swimming pools — as long as they don’t cover more than 50% of the garden and meet height restrictions.
- Fences and walls: Up to 2 metres high (1 metre if next to a highway).
- Solar panels: On the roof, provided they don’t stick out more than 200mm above the roof surface.
When You Definitely Need Planning Permission
You’ll typically need a full application for:
- New dwellings (building a new house or converting a building to residential)
- Extensions that exceed PD limits
- Two-storey extensions (although some PD rights exist for these now)
- Side extensions on most properties (can’t exceed 50% of the width of the original house)
- Changes of use (residential to commercial, for example)
- Work that materially changes how a building looks
Conservation Areas and Listed Buildings
If your property is in a conservation area, your PD rights shrink significantly. You’ll generally need permission for any extension visible from a highway, any cladding, satellite dishes on front elevations, and demolition of buildings over 115 cubic metres.
For listed buildings, the rules are even tighter. You need Listed Building Consent for any work that affects the building’s character — inside or out. This is separate from planning permission and applies even to minor things like replacing windows or knocking through internal walls. Here’s the thing: unauthorised work to a listed building is a criminal offence. Don’t risk it.
How to Apply
Applications in England go through the Planning Portal (planningportal.co.uk). You’ll need:
- Completed application form
- Site location plan (1:1250 or 1:2500, with the site edged in red)
- Block plan (1:200 or 1:500 showing the proposal in context)
- Existing and proposed drawings (floor plans and elevations)
- Design and Access Statement (for major applications)
- The correct fee
What It Costs
Planning fees are set nationally. As of 2025:
- Householder application (extensions, alterations): £258
- New dwellings: £578 per dwelling (up to 50 units)
- Change of use: £578
- Listed Building Consent: Free (one small mercy)
- Lawful Development Certificate: £129 (existing) or half the normal fee (proposed)
How Long Does It Take?
The official target is 8 weeks for householder and minor applications, and 13 weeks for major ones. In reality? Many councils take longer. If your LPA misses the deadline, you can appeal to the Planning Inspectorate on grounds of non-determination — but most people just wait it out.
Pre-Application Advice
Most councils offer a pre-application advice service where a planning officer reviews your proposal before you submit formally. Fees vary by council (£50–£600) but this is money well spent for anything beyond a simple extension. James in Leeds was told his rear extension needed redesigning after submitting — £120 of pre-app advice would have saved him £800 in architect revisions and two months of delay.
If Your Application Gets Refused
You can appeal to the Planning Inspectorate within 12 weeks (householder) or 6 months (full applications). Or you can revise and resubmit — the first resubmission within 12 months of refusal is usually free.
Use our free Planning Permission checker to find out whether your project is likely to need a formal application.