Do You Need Planning Permission for a Loft Conversion?

When a loft conversion needs planning permission

A loft conversion counts as permitted development, with no planning application, when the house passes five tests and the work stays within seven limits, the Planning Portal says. If the house fails a test, the work breaks a limit, or permitted development rights have been removed in the area, the same page says an application for householder or full planning permission is required.

The five permitted development tests for the house

The Planning Portal sets five tests for the house itself. The property cannot be a flat or a building containing flats, and the house cannot already have had extra storeys added, been changed to a house from a non-residential use, or been built as a new dwellinghouse under permitted development rights.

The fifth test is where the house stands. It cannot be on Article 2(3) designated land, which the Planning Portal says includes a conservation area and an area of outstanding natural beauty.

The seven permitted development limits for the work

On a house that passes all five tests, the conversion itself has to stay within seven limits, and breaking any one of them means applying for planning permission, the Planning Portal says.

Limit	The rule
Volume	No more than 40 cubic metres of extra roof space on a terraced house, or 50 cubic metres on any other house
Height	No higher than the existing roof
Principal elevation	Nothing beyond the existing roof slope on the principal elevation, where it fronts a highway
Materials	Similar in appearance to the existing house
Balconies	No verandas, balconies or raised platforms
Side-facing windows	Obscure-glazed, with any opening part 1.7 metres above the floor
Eaves	Kept, with the enlargement set back at least 20cm from the original eaves

The 40 and 50 cubic metre allowance

The volume limit counts the roof space a conversion adds, not the loft you already have. The Planning Portal allows up to 40 cubic metres on a terraced house and up to 50 cubic metres on any other house, so a semi-detached or detached house gets the larger allowance.

Dormer loft conversions and planning permission

Checkatrade describes a dormer as a box structure with vertical windows that adds headspace and floor space. Because that box stands out from the roof slope, a dormer on the principal elevation, where that side of the house fronts a highway, goes beyond the existing roof slope, which the Planning Portal does not allow under permitted development.

Wherever it sits, a dormer also needs materials similar in appearance to the house, obscure glazing in any side-facing window with opening parts 1.7 metres above the floor, and a set-back of at least 20cm from the original eaves, the Planning Portal says. Checkatrade says a mansard, which alters a roof slope to an almost vertical angle, is far more involved structurally than a full-width dormer and is likely to need planning permission.

Conservation areas and listed buildings in Nottingham

A conservation area is Article 2(3) designated land, so under the Planning Portal’s tests a loft conversion on a house in one needs a planning application.

A listed building needs listed building consent for most building work, internal and external, and the council’s My Property map, at geoserver.nottinghamcity.gov.uk/myproperty, shows whether a property is listed or in a conservation area, Nottingham City Council says.

Article 4 Directions in Nottingham

An Article 4 Direction removes the right to carry out certain types of permitted development, so planning permission is needed instead, Nottingham City Council says. The city’s directions cover specific properties, mostly within conservation areas, in six areas.

• Devonshire Promenade
• Foxhall Road
• Sneinton
• Strelley Village
• Waterloo Promenade
• Wellington Terrace

The directions restrict minor building work such as small extensions, outbuildings and changes to windows and doors, and the council advises using its Minor Works Enquiry Service before doing work in those areas.

How to check whether your loft conversion is permitted development

Check the house before the design, because a house that fails one of the five tests, or stands where permitted development rights have been removed, needs a planning application under the Planning Portal’s rules however the loft is designed.

Applying for planning permission for a loft conversion

If the conversion fails any check, Checkatrade advises applying before any work starts, and says a decision can take up to 13 weeks on a complex or large project, while simpler applications are often quicker, sometimes under 8 weeks.

Some loft conversion companies handle the planning side as part of the job. Of the ten Nottingham loft conversion companies we compare, Lady Bay Loft Conversions takes care of design, planning permissions and building control certificates, and Roof Rooms supplies full working plans and structural calculations.

Building regulations and the Party Wall Act

Whether or not the conversion needs planning permission, building regulations approval is required to convert a loft into a liveable space, the Planning Portal says. The Party Wall etc. Act 1996 lets an owner cut into a party wall shared with a neighbour to take the bearing of a beam, and GOV.UK’s explanatory booklet names a loft conversion as an example.