Free tool
Do I Need Planning Permission?
Answer a few questions about your London project and get an instant assessment of whether you need planning permission or qualify for Permitted Development.
1
Project
2
Property
3
Specifics
4
Result
Step 1 of 4
What type of project are you planning?
Select the project type that best describes what you want to do. We will check whether it falls within Permitted Development rights.
Rear Extension (single storey)
Side Extension
Wraparound Extension
Double Storey Extension
Loft Conversion (dormer)
Loft Conversion (Velux only)
Mansard Roof Extension
Garage Conversion (integral)
Garage Conversion (detached)
Garden Outbuilding
Change of Use
Step 2 of 4
Tell us about your property
Your property type and designations affect your Permitted Development rights. Listed buildings and flats have different rules.
Property type
Is the property listed?
Listed buildings have no Permitted Development rights. All external and most internal alterations require Listed Building Consent and usually full planning permission.
Is it in a conservation area?
Conservation areas restrict many Permitted Development rights, particularly for extensions, dormers, and outbuildings. Side extensions, rear dormers, and cladding changes typically require planning permission.
Has any previous extension been built?
London borough
Step 3 of 4
Project specifics
These measurements determine whether your project stays within Permitted Development limits under the GPDO (General Permitted Development Order).
How deep will the extension be?
Volume to be added
Which elevation will the dormer face?
Maximum height of the outbuilding
Distance from boundary
Will total outbuildings cover more than 50% of the garden?
What work is involved?
Will the side extension be single storey?
No additional measurements are needed for this project type. Click "See my result" to get your assessment.
Why this result?
MCIAT chartered
98% approval rate
30% below architects