Do you need planning permission for a loft conversion?
Most loft conversions are permitted development if the added roof space stays within 40 cubic metres (terraced houses) or 50 cubic metres (semi detached and detached), and the dormer stays off the front roof.
Across the 233 councils we track, 82% of 78,356 decided loft conversion or dormer applications were approved, and typical council decision times run 8 to 9 weeks (public planning record to 10 Jul 2026).
First, about your home
Now, about a loft conversion
0 of 7 questions answered. Answer them all to see where your project stands. Not sure is always an option.
What actually happens in your council
If you do end up applying, real decisions show what to expect. Pick your council for its approval rate and typical decision time for loft conversion or dormer applications, from the public planning record.
The rules this checker tests, cited
England’s permitted development limits for a loft conversion, checked against the official guidance on 2026-07-17. Every rule links to its source.
- Roof enlargements must not add more than 40 cubic metres on a terraced house, or 50 cubic metres on a semi detached or detached house. The allowance is cumulative: any previous roof extension counts against it. GPDO Schedule 2, Part 1, Class B, paragraph B.1(d) (opens in new tab)
- A dormer must not extend beyond the roof slope of the principal elevation that fronts a road. GPDO Schedule 2, Part 1, Class B, paragraph B.1(c) (opens in new tab)
- A roof enlargement must not be higher than the highest part of the existing roof. The dormer must also sit back at least 20 centimetres from the original eaves, and use materials of similar appearance to the existing house. GPDO Schedule 2, Part 1, Class B, paragraphs B.1(b) and B.2(b) (opens in new tab)
- Balconies, verandas and raised platforms are not permitted development on a roof enlargement. GPDO Schedule 2, Part 1, Class B, paragraph B.1(e) (opens in new tab)
- On designated land (a conservation area, National Park, the Broads, an area of outstanding natural beauty or a World Heritage Site), roof enlargements such as dormers are not permitted development and need a planning application.
Building Regulations are separate from planning. A loft conversion always needs Building Regulations approval: floor structure, fire escape, stairs and insulation are all covered.
If permission is needed: usually a £548 application in England (fees from 1 April 2026, indexed each year, per the official fee guide (opens in new tab)). A Lawful Development Certificate for a proposed project is £274.
If you take it forward
Real planning history beats promises. See which architects and agents know your council, check approval odds by council and project, or browse traders with public evidence:
Common questions
Do I need planning permission for a loft conversion in England?
Often not: Most loft conversions are permitted development if the added roof space stays within 40 cubic metres (terraced houses) or 50 cubic metres (semi detached and detached), and the dormer stays off the front roof. Every limit has to be met, the rights apply to houses (not flats), and they can be removed locally by an Article 4 direction or a condition on an earlier permission. A Lawful Development Certificate from your council is the way to be certain.
Will the conversion add more than 40 cubic metres (terraced house) or 50 cubic metres (semi detached or detached) of roof space?
Roof enlargements must not add more than 40 cubic metres on a terraced house, or 50 cubic metres on a semi detached or detached house. The allowance is cumulative: any previous roof extension counts against it. Source: GPDO Schedule 2, Part 1, Class B, paragraph B.1(d).
Will any part of it extend beyond the roof slope at the front of the house?
A dormer must not extend beyond the roof slope of the principal elevation that fronts a road. Source: GPDO Schedule 2, Part 1, Class B, paragraph B.1(c).
Will any part of it be higher than the existing ridge (the top of the roof)?
A roof enlargement must not be higher than the highest part of the existing roof. The dormer must also sit back at least 20 centimetres from the original eaves, and use materials of similar appearance to the existing house. Source: GPDO Schedule 2, Part 1, Class B, paragraphs B.1(b) and B.2(b).
Will it include a balcony, veranda or raised platform?
Balconies, verandas and raised platforms are not permitted development on a roof enlargement. Source: GPDO Schedule 2, Part 1, Class B, paragraph B.1(e).
How much does a planning application for a loft conversion cost?
If permission is needed, this kind of project is usually a £548 application in England (fees from 1 April 2026, indexed annually). A Lawful Development Certificate for a proposed project costs half the application fee.
Guidance from the public rules, not legal advice. Your council has the final say. The rules on this page are England law; Wales, Scotland and Northern Ireland have their own versions.
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