Do I Need Planning Permission?Free Permitted Development Checker
Instantly check if your extension, loft conversion, outbuilding or home improvement needs planning permission under UK GPDO rules. Get your answer in minutes, completely free.
What is Permitted Development?
Permitted development rights allow UK homeowners to make certain improvements and extensions to their homes without needing to apply for formal planning permission. These rights are granted by the General Permitted Development Order (GPDO) 2015 (as amended) and can save you time, money, and paperwork.
However, permitted development comes with strict conditions and limitations. Your extension must meet specific size limits, height restrictions, and design requirements. If your property is in a conservation area, National Park, or is a listed building, additional restrictions may apply.
Our free checker helps you navigate these complex rules. Simply answer a few questions about your property and proposed project, and we'll tell you whether it's likely to qualify as permitted development or if you'll need to apply for planning permission.
How to Check If You Need Planning Permission
Our free tool guides you through the GPDO rules in three simple steps
Tell Us About Your Property
Enter basic details about your home: property type, location, and whether you're in a designated area like a conservation zone.
Describe Your Project
Answer questions about your proposed extension, loft conversion, or outbuilding including size, height, and position.
Get Instant Results
Receive clear guidance on whether your project qualifies as permitted development or if you need to apply for planning permission.
Frequently Asked Questions
Common questions about planning permission and permitted development
Do I need planning permission for a single storey extension?
In most cases, single storey rear extensions up to 4 metres (detached houses) or 3 metres (other houses) don't need planning permission under permitted development rights. Extensions between 4-8m (detached) or 3-6m (other) require prior approval through the neighbour consultation scheme.
What is permitted development?
Permitted development rights allow homeowners to make certain improvements to their homes without applying for planning permission. These rights are granted by the General Permitted Development Order (GPDO) 2015 and cover extensions, loft conversions, outbuildings, and more.
Can I build an extension without planning permission?
Yes, many extensions can be built under permitted development rights without formal planning permission. However, your extension must meet specific size limits, height restrictions, and other conditions. Our free checker helps you determine if your project qualifies.
How big can I extend my house without planning permission?
For single storey rear extensions: up to 4m depth for detached houses or 3m for semi-detached/terraced (or up to 8m/6m with prior approval). For two storey extensions: maximum 3m depth. Side extensions must be single storey and less than half the width of the original house.
Do I need planning permission for a loft conversion?
Most loft conversions are permitted development, but there are volume limits: 50 cubic metres for detached/semi-detached houses, 40 cubic metres for terraced houses. Dormers cannot extend beyond the existing roof slope facing the highway.
Do I need planning permission for an outbuilding or garden room?
Outbuildings including sheds, garden offices, and summer houses are usually permitted development if: they're single storey, not forward of the principal elevation, don't cover more than 50% of the garden, and meet height limits (2.5m near boundaries, 4m maximum with pitched roof).
Permitted Development Size Limits at a Glance
Quick reference for common home improvements (subject to conditions)
Single Storey Rear Extension
- Detached: Up to 4m depth (8m with prior approval)
- Semi/Terraced: Up to 3m depth (6m with prior approval)
- Max height: 4m (3m within 2m of boundary)
Two Storey Extension
- Max depth: 3m from rear wall
- Min distance: 7m from rear boundary
- Roof pitch: Must match existing house
Loft Conversion
- Detached/Semi: Up to 50m³ volume
- Terraced: Up to 40m³ volume
- Dormers: Not on front roof slope
Outbuildings & Garden Rooms
- Max height: 4m (pitched) / 3m (flat)
- Near boundary: 2.5m max if within 2m
- Coverage: Max 50% of garden area
Porches
- Floor area: Max 3 square metres
- Max height: 3m above ground level
- Distance: 2m+ from boundary/highway
Fences, Gates & Walls
- Adjacent to highway: Max 1m height
- Elsewhere: Max 2m height
- Listed buildings: Check restrictions
These are simplified guidelines. Many additional conditions apply.
Check Your Specific ProjectWhy Use PRAITE?
100% Free Forever
No hidden fees, no premium tiers, no registration required. Our assessment tool is completely free for all UK homeowners.
Based on Official GPDO Rules
All assessments follow the General Permitted Development Order 2015 (as amended), the official UK planning legislation.
Instant Results
Get your answer in minutes, not days. No waiting for callbacks or appointments with planning consultants.
Important Notice
PRAITE provides guidance based on the General Permitted Development Order 2015 (as amended). This is not a substitute for professional advice. Only your Local Planning Authority can provide a definitive ruling on whether your project requires planning permission. We strongly recommend applying for a Lawful Development Certificate for complete certainty before starting any building work.
Ready to Check Your Project?
Find out in minutes whether your extension, loft conversion, or outbuilding needs planning permission. It's free and takes just 5 minutes.
Start Free Assessment Now