Loft conversion

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' section².
• “enlargement of a dwellinghouse by construction of additional storeys” (Schedule 2, Part 1 Class AA) which are detailed in our ‘Additional Storeys/Extending Upwards’ section³.

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:

1. The eaves of the original roof are maintained (or reinstated)
2. Any enlargement is set back, so far as practicable, at least 20cm from the original eaves (see pages 35-36 of the Technical Guidance⁴ below for more details)
3. 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

Definitions

Balcony

The Government’s technical guidance states that: “A balcony is understood to be a platform with a rail, balustrade 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.

View 'Permitted development for householders – Technical guidance' on Gov.uk⁵

1. https://www.legislation.gov.uk/uksi/2015/596/schedule/2/part/1/crossheading/class-b-additions-etc-to-the-roof-of-a-dwellinghouse
2. https://www.planningportal.co.uk/permission/common-projects/roof/roof-planning-permission
3. https://www.planningportal.co.uk/permission/common-projects/additional-storeys-extending-upwards/planning-permission
4. https://www.gov.uk/government/publications/permitted-development-rights-for-householders-technical-guidance
5. https://www.gov.uk/government/publications/permitted-development-rights-for-householders-technical-guidance