Permitted Development Rights London 2026: Complete Guide
Build your extension without planning permission. Everything you need to know about permitted development rights in London, including Article 4 directions by borough.
What Are Permitted Development Rights?
Permitted development rights allow you to make certain changes to your home without needing planning permission. This can save you 2-4 months and £500-2,000 in planning fees. However, London has specific restrictions that make it more complex than the rest of the UK. Full details about permitted development rights are available on the Planning Portal.
Quick Answer
In London, permitted development allows rear extensions up to 8m (detached) or 6m (terraced/semi). However, 60% of London properties have restrictions from conservation areas or Article 4 directions.
6-8m
Max rear depth
2-4 months
Time saved
60%
Properties restricted
Check your specific property constraints
Free Property CheckPermitted Development Size Limits by Extension Type
| Extension Type | Detached | Semi/Terraced | Prior Approval |
|---|---|---|---|
| Single rear (depth) | Up to 8m | Up to 6m | If 6-8m or 3-6m |
| Single rear (height) | 4m max | 4m max | — |
| Two-storey rear | 3m max | 3m max | Not required |
| Side extension | Half width | Half width | If 7m rule |
| Loft conversion | 50m³ volume | 40m³ volume | Not required |
| Conservation area | Restricted | Restricted | Required |
* All measurements from original rear wall. Conservation areas have significantly reduced permitted development rights.
Single-Storey Rear Extensions
You can build under permitted development if your extension is:
Detached House
- Maximum 8m from rear wall
- Maximum 4m height
- Maximum 3m to eaves
Terraced/Semi-Detached
- Maximum 6m from rear wall
- Maximum 4m height
- Maximum 3m to eaves
Important: Extensions 3-4m or 6-8m deep require Prior Approval for neighbour notification.
Not sure if your extension qualifies?
Check your exact permitted development limits including conservation areas, Article 4 directions, and previous extensions on your property.
Two-Storey Rear Extensions
Much more restrictive. You can build under permitted development only if:
- Maximum 3m from rear wall (all house types)
- No extension beyond the rear of the side wall
- First floor rear wall must be at least 7m from boundary
- Maximum 4m total height (not exceeding original ridge)
Side Extensions Under Permitted Development
Side extensions (including side returns) can be built under permitted development if:
- Maximum width: half the width of the original house
- Single storey only (maximum 4m height)
- Must be at least 7m from any boundary opposite the side
- No balconies, verandas, or raised platforms
Side return note: Most London terraced houses have side returns narrower than 7m from the boundary, which means they require planning permission in most cases.
Loft Conversions Under Permitted Development
You can convert your loft under permitted development if:
- Volume increase doesn't exceed 40m³ (terraced) or 50m³ (detached/semi)
- No extension beyond existing roof plane facing a highway
- Rear dormer must be at least 20cm from eaves and party walls
- Materials similar to existing house
- No verandas, balconies, or raised platforms
Article 4 Directions: The London Exception
This is where London gets complicated. Many London boroughs have Article 4 directions that remove permitted development rights in specific areas or for specific types of development.
Boroughs with Extensive Article 4 Directions
High Restriction Boroughs
- Westminster (most areas)
- Camden (conservation areas)
- Kensington & Chelsea (most areas)
- Islington (conservation areas)
- Hackney (many areas)
- Tower Hamlets (conservation areas)
- Greenwich (conservation areas)
- Richmond (conservation areas)
These boroughs often require planning permission even for standard rear extensions.
In a conservation area or Article 4 zone? Our AI checks your specific property constraints instantly.
Check your address →Conservation Areas and Listed Buildings
If your property is in a conservation area:
- NO side extensions under permitted development
- NO roof extensions (lofts/dormers) on rear or side
- Reduced permitted development rights for rear extensions
- Most external changes require planning permission
If your property is listed:
- Almost no permitted development rights
- Need both planning permission AND listed building consent
- Significantly longer approval process (4-6 months typical)
When You've Already Used Permitted Development Rights
Permitted development rights are cumulative since 1948. If a previous owner built an extension using permitted development rights, you may have less (or zero) permitted development rights remaining. This is why a professional check is essential.
Prior Approval vs Planning Permission
| Aspect | Prior Approval | Planning Permission |
|---|---|---|
| Timeline | 6 weeks | 8-12 weeks |
| Cost | £96 | £258-462 |
| Scope of review | Impact on neighbours only | Full design review |
| Neighbour consultation | Yes (adjacent only) | Yes (wider area) |
| Design changes | Limited | Can be required |
How to Check Your Permitted Development Rights
To definitively know if you can build under permitted development:
- 1Check if you're in a conservation area (your borough's planning portal)
- 2Check for Article 4 directions in your area
- 3Review any previous extensions (planning portal or survey)
- 4Measure your proposed extension carefully
- 5Get professional assessment (recommended before investing in design)
Free AI Assistant
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Summary
Permitted development rights can save months and money if you qualify. However, London's Article 4 directions and conservation areas make it more complex than other UK regions.
Before you start design work, get a professional permitted development assessment. Our free checker can save thousands if you discover you need planning permission instead.
Frequently Asked Questions
Can I combine rear and side extensions under permitted development?
Yes, but they're calculated separately. Each must meet its own size limits, and the combined volume cannot exceed your total allowance.
Do I need building regulations approval for permitted development?
Yes, always. Permitted development rights only exempt you from planning permission. You still need building regulations approval for structural, fire safety, and energy efficiency requirements.
Can I lose my permitted development rights?
Yes. Your borough can impose an Article 4 direction at any time (with notice). If you're considering permitted development, start design and submit Prior Approval before any restrictions are announced.
What if I'm partly in a conservation area?
If any part of your property boundary touches a conservation area, the stricter conservation area rules apply to your entire property.
Can I appeal a Prior Approval refusal?
Yes, you can appeal within 6 months. However, appeals can take 3-6 months to resolve. Often faster to revise and resubmit or apply for full planning.
How much does it cost to check permitted development rights professionally?
Professional permitted development assessments typically cost £150-300. However, checking your property details, conservation area status, and Article 4 directions yourself is free using council planning portals and online permitted development checkers.
What happens if I build without permitted development rights?
Building without permission (when you don't have permitted development rights) can result in enforcement action. The council can issue an enforcement notice requiring demolition within 4-8 weeks. This can cost £20,000-50,000+ to rectify, plus legal fees.
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Or email hello@mayfairstudio.co.uk · 07405 920944