Converting the loft of a house is considered to be permitted development (not requiring planning permission) subject to the following 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 20151 (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.
- “enlargement of a dwellinghouse by construction of additional storeys” (Schedule 2, Part 1 Class AA) which are detailed in our ‘Additional Storeys/Extending Upwards’ section.
If these limits and conditions are not met, or Permitted Development rights have been removed in the area, then an application for Householder/Full Planning Permission will be required.
The current house:
- Is not a building containing one or more flats, or a flat contained within such a building
- Has not already had additional storeys added to it under permitted development rights
- Was not changed to be used as a house (from a previous non-residential use) under permitted development rights.
- Was not built as a ‘New Dwellinghouse’ under permitted development rights.
- Is not on Article 2(3) designated land*
Limitations on the proposed development:
- Materials must be similar in appearance to the existing house
- Volume of enlargement (including any previous enlargement) must not exceed the original roof space by more than:
- 40 cubic metres for terraced houses; or
- 50 cubic metres otherwise
- Must not exceed the height of the existing roof.
- On the principal elevation of the house (where it fronts a highway), must not extend beyond the existing roof slope.
- Must not include:
- verandas, balconies* or raised platforms; or
- installation, alteration or replacement of any chimney, flue, or ‘soil and vent pipe’
- Side-facing windows must be obscure-glazed; and, if opening, to be 1.7 metres above the floor of the room in which they are installed.
- Construction must ensure that:
- The eaves of the original roof are maintained (or reinstated)
- Any enlargement is set back, so far as practicable, at least 20cm from the original eaves (see pages 35-36 of the Technical Guidance2 below for more details)
- The roof enlargement does not overhang the outer face of the wall of the original house
With the exceptions that:
- Points 1 and 2 do not apply to the relevant parts of any hip-to-gable enlargement.
- None of these three points apply to the relevant parts of any enlargement that joins the original roof to the roof of a side or rear extension
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The Government’s technical guidance states that: “A balcony is understood to be a platform with a rail, ballustrade or parapet projecting outside an upper storey of a building. A ‘Juliet’ balcony, where there is no platform and therefore no external access, would normally be permitted development.”
Article 2(3) designated land
This is defined as land within:
- a conservation area; or
- an area of outstanding natural beauty; or
- an area specified by the Secretary of State for the purposes of enhancement and protection of the natural beauty and amenity of the countryside; or
- the Broads; or
- a National Park; or
- a World Heritage Site.
Permitted Development for householders – Technical Guidance
You are strongly advised to read the technical guidance produced by the Government to help understand how permitted development rules might apply to your circumstances.