

LOFT CONVERSIONS AND ROOF EXTENSIONS
DO YOU NEED PLANNING PERMISSION?
Loft conversions can be a great way of extending habitable space in a house without the need for a planning application. Planning permission is not usually required ahead of internal loft conversion works. Building Regulations approval and other consents are likely to be required in all instances.
External extensions to a roof space are more likely to require planning permission, however.
Planning applications cost money, take time, and require an assessment to be made by a local planning authority officer. Your neighbours will be consulted and can object to your proposals.
However, as with any extension to your house, you can undertake certain works without the need to apply for planning permission – subject to ‘permitted development’ rules being met in terms of extension size, type and location.
The relevant rules are set out in the Town and Country Planning (General Permitted Development) (England) Order 2015, as amended.
LOFT CONVERSIONS AND ROOF EXTENSIONS – PERMITTED DEVELOPMENT RULES
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 GPDO.
There are different rules for:
- “any other alteration to the roof of a dwellinghouse” (Schedule 2, Part 1, Class C), which relate to the insertion of ‘skylights’ or re-roofing of roofs
- “enlargement of a dwellinghouse by construction of additional storeys” (Schedule 2, Part 1 Class AA)
An extension to a roof is classed as ‘permitted development’, not needing a planning application, where:
The height of the extension does not exceed the height of the highest point of the existing roof
The extension does not extend beyond the plane of any existing roof slope, which forms the principal elevation (usually the front) of the dwellinghouse and fronts a highway
The extension or alteration doesn’t consist of or include the construction or provision of a veranda, balcony*, or raised platform
The cubic content of the enlargements, as well as that of any previous enlargements to the roof, doesn’t exceed the cubic content of the original roof space by more than 40 cubic metres in the case of a terraced house or 50 cubic metres in any other case
*Balconies
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.”
CONDITIONS
Development is permitted for roof extensions as described above, only subject to the following conditions:
The current house:
Must be a ‘dwellinghouse’ and does not contain any flats
Has not already had additional storeys added to it under previously used permitted development rights
Has 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 (see protected areas section below)
Also,
The materials used in any exterior work must be of a similar appearance to materials used in the existing house
Any window inserted in a wall or roof slope forming a side elevation of the house must be obscure glazed and be non-opening unless the opening parts are more than 1.7 metres above the floor of the room in which the window is installed
Roof extensions, apart from hip to gable ones, must be set back, as far as practicable, at least 20 centimetres from the eaves of the original roof. If removed, the existing eaves must be reinstated
Other than in the case of an enlargement which joins the original roof to the roof of a rear or side extension, no part of the enlargement extends beyond the outside face of any external wall of the original dwellinghouse


SEPARATE RULES RELATE TO:
- Re-roofing a roof
- Inserting sky-lights (e.g. ‘Velux’-style windows in a roof)
- Adding an extra storey to a house
- Porches
- Decking, balconies and raised platforms
- TV aerials or satellite dishes
- chimneys, flues or soil and vent pipes
- Any alteration to the roof of the existing house
- Changes of use
PERMITTED DEVELOPMENT – PROTECTED AREAS – ROOF EXTENSIONS
If you live in any of the areas listed below, additional limitations on ‘permitted development’ will apply:
- Conservation Areas
- Areas of Outstanding Natural Beauty
- National Parks
- the Broads
- World Heritage Sites
In these areas, roof extensions are not permitted development and will require an application for planning permission.
REMOVAL OF PERMITTED DEVELOPMENT RIGHTS
Permitted development rights can also be removed by your local planning authority, either through the addition of a Condition on a previous planning permission, or through imposition of an Article 4 Direction.
CONTACTING YOUR LOCAL PLANNING AUTHORITY BEFORE COMMENCING WORKS
For the purposes of planning, contact with the local planning authority is generally only necessary before carrying out permitted development where:
- ‘prior approval’ from the local planning authority is required under PD rules
- a ‘neighbour consultation scheme’ is in place
- the local planning authority has a Community Infrastructure Levy in place which requires developers to contact the local planning authority before carrying out permitted development. Failure to do this may result in the local planning authority imposing a surcharge on a developer
- the permitted development rights require the developer to notify the local planning authority of a change of use
Schedule 2 of the GPDO sets out when any advance notification is required. If you are in any doubt, contact your local planning department or seek professional advice.
PERMITTED DEVELOPMENT RIGHTS FOR FLATS, SHOPS AND BUSINESSES
Permitted development rights under Part 1 of the GPDO only apply to houses – they do not apply to flats, maisonettes or other buildings.
Check out our guides to non-householder PD rights (through the menu at the top of this page).
PERMITTED DEVELOPMENT RIGHTS AND CIL
If a development is over 100 sq m in size, it may be liable for a charge under the Community Infrastructure Levy (CIL).
Check with your local planning authority whether they use CIL in your area and whether it applies to permitted development.
AND FINALLY …
PD rights are subject to change. The guide above is for general information only and does not constitute advice. Local and site-specific circumstances can differ and affect whether a planning application is needed.
Other consents (such as Building Regulations or notifications under the Party Wall Act) may also be needed.
To determine whether planning permission or other consents are required, seek professional advice or clarification from your local authority before starting works.
TownPlanning.info has an extensive catalogue of articles and guides which help explain the town planning system in England.
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