Do I need planning permission for a conservatory?
Permitted development rules, size limits, and when full planning is required.
Permitted development limits
A conservatory is treated as a single-storey rear extension. Under Class A of the General Permitted Development Order, you don't need planning if it meets all of the following:
- Single-storey only (no second floor)
- Maximum eaves height 3m (4m if within 2m of a boundary)
- Maximum overall height 4m
- Maximum projection from rear wall: 3m (terraced/semi-detached) or 4m (detached)
- Total area covered does not exceed 50% of the original house garden/curtilage
- Materials look similar to existing house (or are predominantly glass)
- Not in front of the principal elevation (i.e. not a front conservatory)
Larger Home Extension Scheme (sometimes available)
Until separately reviewed, the Larger Home Extension Scheme allows up to 6m rear projection (semi/terrace) or 8m (detached) under prior approval. Requires neighbour consultation. Currently extended through 2025–2026 at time of writing — check current status.
When you DO need planning permission
- Front-of-property conservatory
- Exceeds size limits
- Conservation area, AONB, National Park, Heritage Coast
- Listed building (always needs listed building consent regardless)
- Property has had permitted development rights removed
- Flats or maisonettes (PD doesn't apply)
- Conservatory has solid roof + acts as habitable extension (then it's an extension, not a conservatory)
Building Regulations
True conservatories (mostly glass, separated from house by external doors, no central heating extending in) are EXEMPT from Building Regulations. If the conservatory has a solid roof or is open to the main house, it's treated as an extension and Building Regulations apply.
Official sources
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Frequently asked questions
Up to 3m rear projection (terrace/semi) or 4m (detached). Under 4m total height. Under 50% of garden coverage.
Permitted development is restricted in conservation areas — check with your local council before any work.
Once you put a solid roof on, it's treated as an extension under Building Regulations (insulation, structural calcs all apply). Planning rules are the same.
Worth applying for (£100–£200) if your conservatory is permitted development. Avoids problems when selling later.
Related
Last reviewed: May 2026 · This information is general guidance and not legal advice.
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