Permitted Development Rights

Not all building work requires planning permission. Some smaller projects can be carried out under what is termed Permitted Development Rights.

Permitted development rights

In some areas Permitted Development Rights don’t apply or have been withdrawn. These include Conservation Areas, National Parks, Areas of Outstanding Natural Beauty, World Heritage Sites and the Norfolk and Suffolk Broads. 

Listed building consent is required for work to listed buildings, but that doesn’t necessarily mean Permitted Development Rights have been removed. In sensitive areas Article 4, which aims to retain high-quality architectural features and to preserve and enhance the character and appearance of the built heritage, can remove Permitted Development Rights. Your local council will have more details. 

What can I build under Permitted Development Rights?


Modest extensions can be carried out under Permitted Development. Extensions, both existing and new, and other buildings, should not exceed 50% cent of the total land surrounding a house. Extensions are not allowed to the front facade, and elsewhere must be similar in appearance to the rest of the house. If a different finish is required such as timber cladding, permission will need to be sought. This is not the case for conservatories. 


Side extensions must be single storey with a maximum height of 4m, unless it’s within 2m metres of the boundary and then maximum eaves height must be below 3m. 

Single-storey rear extensions must not extend more than 6m for a semi-detached or terrace, and 8m for a detached property, subject to the Neighbourhood Consultation Scheme. This requires that the relevant Local Planning Authority is informed of the proposed work via a prior approval application.

Two-storey rear extensions are limited to 3m.

Loft conversions

Loft conversionLoft conversions usually fall under Permitted Development, unless there is an existing extension to the house. There are size limits of 40m3 for terraced houses and 50m3 for semi-detached and detached houses. The plane of the existing roof slope must not be exceeded, and balconies or dormers are not permitted.


See Guide to Loft Conversions »



Barn conversions and agricultural land

Changes to Permitted Development Rights for barns and farm buildings took effect in 2018, increasing to five (from three) the number of new homes that can be created from existing agricultural buildings on a farm without securing specific planning permission. This became Class MB in the General Permitted Development order, and it allows for: 

    • up to three large homes with a combined floorspace of 465 sqm
    • up to five smaller homes each no larger than 100 sqm
    • a combination of small and large, of which no more than three may be large homes.

Agricultural buildings

There are several restrictions:

    • The site must have been used only for agricultural purposes.
    • The rule does not apply to building new barns – the barn must have existed in March 2013.
    • The rule does not apply in designated areas such as Conservation Areas.

Commercial building conversions

former-filling-station.jpgPermitted Development allows a change of use for some commercial buildings to be converted to houses. Temporary permitted development rights currently apply in respect of the change of use of premises from an office B1(a) to C3 residential use. This is subject to Prior Approval being sought in respect of flooding, contamination, highways and transport issues and impacts of noise from commercial premises on the intended occupiers of the development. Development must be completed within three years starting with the prior approval date. 

Light industrial buildings can also be converted to dwelling houses subject to limitations and conditions including the prior approval of the local planning authority in respect of certain matters. It is only applicable to applications received on or after 1 October 2017, for which prior approval is granted before 1 October 2020. Development must then be completed within three years of the prior approval date.

Lawful Development Certificates

It is strongly advised to contact the planning department before work begins on any project to confirm that permission is not required. A lawful development certificate can be obtained from the local council to confirm that work can be carried out without permission. 

A free technical guide to Permitted Development can be downloaded. See also the Planning Portal website.


See Guide to Conversions »


Go to Buildings for Conversion »