Single & Double Storey Extension Guidelines?
This guidance reflects temporary increases to the size limits for single-storey rear extensions that must be completed by 30 May 2019, and the associated neighbour consultation scheme.
An extension or addition to your house is considered to be permitted development, not requiring an application for planning permission, subject to the following limits and conditions:
- No more than half the area of land around the “original house”* would be covered by additions or other buildings.
- No extension forward of the principal elevation or side elevation fronting a highway.
- No extension to be higher than the highest part of the roof.
- Single-storey rear extension must not extend beyond the rear wall of the original house* by more than three metres if an attached house or by four metres if a detached house.
- In addition, outside Article 2(3) designated land* and Sites of Special Scientific Interest the limit is increased to 6m if an attached house and 8m if a detached house until 30 May 2019.
- These increased limits (between 3m and 6m and between 4m and 8m respectively) are subject to the prior notification of the proposal to the Local Planning Authority and the implementation of a neighbour consultation scheme. If objections are received, the proposal might not be allowed.
- Maximum height of a single-storey rear extension of four metres.
- Extensions of more than one storey must not extend beyond the rear wall of the original house* by more than three metres.
- Maximum eaves height of an extension within two metres of the boundary of three metres.
- Maximum eaves and ridge height of extension no higher than existing house.
- Side extensions to be single storey with maximum height of four metres and width no more than half that of the original house.
- Two-storey extensions no closer than seven metres to rear boundary.
- Roof pitch of extensions higher than one storey to match existing house.
- Materials to be similar in appearance to the existing house.
- No verandas, balconies or raised platforms.
- Upper-floor, side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor.
- On designated land* no permitted development for rear extensions of more than one storey.
- On designated land no cladding of the exterior.
- On designated land no side extensions.
* The term “original house” means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Although you may not have built an extension to the house, a previous owner may have done so.
* Designated land includes conservation areas, national parks and the Broads, Areas of Outstanding Natural Beauty, and World Heritage Sites.
The planning rules for porches are applicable to any external door to the dwellinghouse.
Adding a porch to any external door of your house is considered to be permitted development, not requiring an application for planning permission, provided:
- the ground floor area (measured externally) would not exceed three square metres.
- no part would be more than three metres above ground level (height needs to be measured in the same way as for a house extension).
- no part of the porch would be within two metres of any boundary of the dwellinghouse and the highway.
Loft Conversion Guidelines?
Planning permission is not normally required. However, permission is required where you extend or alter the roof space and it exceeds specified limits and conditions.
These are specific to “the enlargement of a dwellinghouse consisting of an addition or alteration to its roof” as detailed in Schedule 2, Part 1, Class B of the The Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended).
There are different rules for “any other alteration to the roof of a dwellinghouse” (Schedule 2, Part 1, Class C) which are detailed in our ‘Roof’ section.
A loft conversion for your house is considered to be permitted development, not requiring an application for planning permission, subject to the following limits and conditions:
- A volume allowance of 40 cubic metres additional roof space for terraced houses*
- A volume allowance of 50 cubic metres additional roof space for detached and semi-detached houses*
- No extension beyond the plane of the existing roof slope of the principal elevation that fronts the highway
- No extension to be higher than the highest part of the roof
- Materials to be similar in appearance to the existing house
- No verandas, balconies or raised platforms
- Side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor
- Roof extensions not to be permitted development in designated areas**
- Roof extensions, apart from hip to gable ones, to be set back, as far as practicable, at least 20cm from the original eaves
- The roof enlargement cannot overhang the outer face of the wall of the original house.