Householder rights to build certain extensions and conversions without applying for full planning permission. Subject to size limits, setback rules, and material matching.
Permitted development is planning permission granted nationally by the Town and Country Planning (General Permitted Development) (England) Order 2015, so no application is needed provided every limitation and condition is met. Householder rights sit in Schedule 2, Part 1, Classes A to H.
A rear extension of 3m on a terrace or semi and 4m detached, doubling under prior approval; 40 or 50 cubic metres of added roof volume; a side extension up to half the original house width; and outbuildings, all within 50% of the curtilage.
| Limit | Terrace | Semi | Detached |
|---|---|---|---|
| Rear depth, as of right | 3m | 3m | 4m |
| Rear depth, prior approval | 6m | 6m | 8m |
| Maximum height, single storey | 4m | 4m | 4m |
| Eaves within 2m of a boundary | 3m | 3m | 3m |
| Added roof volume, Class B | 40 m³ | 50 m³ | 50 m³ |
| Outbuilding height within 2m of a boundary | 2.5m | 2.5m | 2.5m |
| All extensions and outbuildings | 50% of curtilage | 50% | 50% |
Source: Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 1, Classes A, B and E, as amended, read at 1 September 2026. Nothing in Part 1 applies to a flat or maisonette, and Article 2(3) removes Class A side extensions, cladding and Class B entirely inside a conservation area. ‘Original’ means the house as built or as it stood on 1 July 1948.
Class A covers extensions and alterations: single-storey rear extensions to 3 m for an attached house or 4 m for a detached one, up to 4 m high, with side extensions limited to half the width of the original house. Class B covers roof extensions within 40 m³ for a terrace and 50 m³ for a semi or detached house. Class C covers rooflights. Class E covers outbuildings, and Class G covers chimneys and flues.
The larger home extension prior approval route allows 6 m for an attached house and 8 m for a detached one, subject to a £249 application, a 21-day neighbour consultation and a six-week determination.
Conservation areas and National Landscapes restrict several classes. An Article 4 direction can withdraw any of them. A condition on the original planning permission — very common on estates built since the 1980s — can remove them entirely. Flats and maisonettes have no householder permitted development at all, and listed buildings still need listed building consent.
Rights are also cumulative and measured against the *original* house as built or as it stood on 1 July 1948. A previous owner's extension consumes the allowance.
A Lawful Development Certificate at £274, determined in eight weeks. It is not required, but it converts a judgement about volume or eaves height into a binding decision, and conveyancing solicitors ask for it.
A worked Greenwich example of permitted development: with 20 conservation areas — the Greenwich Town Centre (World Heritage Site) Conservation Area and the Blackheath Conservation Area among the best known — Royal Borough of Greenwich (Greenwich Council) sees permitted development constantly, and there is no borough-wide Article 4 direction, so permitted development generally survives outside conservation areas. Where permitted development pushes a Greenwich scheme out of permitted development, the route becomes a £548 application decided in 8 weeks rather than a £249 prior approval in 6 weeks.
| Legal basis | GPDO 2015, Schedule 2, Part 1 |
|---|---|
| Rear extension, attached house | 3 m (6 m with prior approval) |
| Rear extension, detached house | 4 m (8 m with prior approval) |
| Roof volume, terrace / semi | 40 m³ / 50 m³ |
| Prior approval fee and period | £249, 6 weeks |
| Flats and maisonettes | No householder rights |
No. Part 1 of Schedule 2 applies to dwellinghouses, not flats or maisonettes.
Yes. Allowances are cumulative against the original house.
Not for straightforward permitted development, though a Lawful Development Certificate is strongly advisable.
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