Permitted Development Rights: A simplified guide 

Unlocking your property's potential

Permitted Development rights were put in place by the Town and Country Planning  Act of 1948. They allow householders to improve and extend their homes without the need to apply for planning permission.

Rules for permitted development are structured in Parts which are divided into Classes. In this brief guide we are going to focus on Classes A,B,C and E ( included in Part 1), which cover extensions generally. Note that Permitted Development rights do not apply to flats or maisonettes.

In any case, extensions (including any existing extensions to the original house) and other buildings cannot exceed 50% of the curtilage. This rule applies to all classes.

1- Ground Floor Single-storey Rear and Side Extensions (class A):

-A single-storey extension must not extend beyond the rear of the original house by more than four metres for a detached house, or by more than three metres in any other case*. Also, the total height of the extension must not exceed four metres.

-If the extension is less than or equal to two metres from a boundary, it cannot be higher than 3m.

-For a side extension, the width must not be greater than half the width of the original house.

-For a side extension, the maximum height is 4 metres, 3 metres if the extension is within 2 metres of a boundary.

 *The neighbour consultation scheme

The neighbour consultation scheme applies to larger extensions built under the increased permitted development rights that are in place until May 2019 for householders’ single-storey rear extensions.

Permitted Development Rights that can be increased are as follows:

 -A single-storey extension can be larger, up to 8 metres for a detached house, or 6 metres in any other case. These larger extensions are not allowed for houses on ‘Article 2(3) land’ ( see sensitive land below) or on a site of special scientific interest. The height restriction remains the same.

Householders wishing to benefit from these enlarged PD Rights, should notify their local authority, who will then consult the adjoining neighbours and property owners regarding any potential impact on light and amenity. If they have any objections, the local planning authority will make the final decision on whether the impact on the amenity of adjoining properties is acceptable and whether the proposed work can be carried out.

 - Two-storey Extensions (class A):

 The extended part of the house can be a two-storey extension, or just an addition of a storey onto a part of the house which has already been added under permitted development in the past. In no case can the entire extension of the original building extend beyond the rear existing wall by more than 3 metres.

Also, where the extension of the house has more than one storey, it must be a minimum of 7 metres away from any boundary of its curtilage which is opposite the rear wall of the house being enlarged.

2-Loft Dormer Extensions (class B and C)

 - Any roof space created must not increase the volume of the original roof space by more than 40 cubic metres for terraced houses and 50 cubic metres in any other case.

 -The materials used should be of similar appearance to those in the existing house.

 -The rear edge of the new dormer closest to the eaves of the original roof should be not less than 0.2 metres measured along the roof slope from the edge of the eaves, unless this is not possible for practical or structural reasons.

Also, you should consider protected species when planning a loft conversion. A survey may be required, and if bats are found, a licence may be needed.

3- New Roof lights (class C)

-Any window located on a roof slope forming a side elevation must be obscure-glazed and non-opening unless it is more than 1.7 metres above the floor level of the room.

-The protrusion of roof light/window and its frame must not exceed 0.15m

4- Outbuildings (class E)

 New buildings cannot be used for ¨normal¨ residential use, such as a bedroom, bathroom, kitchen or a self-contained apartment.

-The new building must have a single storey with a maximum height of 3 metres. If it has a pitched roof, 2.5 m at the eaves and a maximum ridge height of 4 metres. However, if the building is equal to or closer than 2 metres from a boundary it should not exceed 2.5m in height in any case.

For a dwelling house which is on sensitive land (see below),  the total area of ground covered by buildings, enclosures, pools and containers situated more than 20 metres from any wall of the dwelling house cannot be more than 10 square metres.

 5- PD Rights Exceptions/exclusions, Sensitive land

There are some exclusions which apply to permitted development rights:

-Protected areas known as ‘Article 2(3) land’, which include:

·       Conservation areas

·       Areas of Outstanding Natural Beauty

·       National Parks

·       The Broads

·       World Heritage Sites

There are other land areas known as ‘Article 2(4) land’, which include land within a National Park, the Broads or certain land outside the boundaries of a National Park.

-Permitted development rights can be removed by the local planning authority, by means of an Article 4 directive.

-Permitted development rights can be expanded via a Local Development Order or Neighbourhood Development Order.

This is a simplified and informative guide that does not aim to cover 100% of PD rights matters, but the cases presented above cover most of the situations that you could face. In case of doubt, always get in touch with a professional. We also always advise people to get a Certificate of Lawfulness from their local planning authority before starting any work. 

A Lawful Development Certificate application might require architectural documents to be prepared and submitted, and we ALEZ Architecture & Interiors would be delighted to help you through this process, so please do not hesitate to get in touch if necessary.

This is a simplified  guide and is not a conclusive source of legal information. Land constraints might affect your development. A legal professional will be able to provide precise advice on this if needed. For a complete source of information you can visit:

The Town and Country (General Permitted Development)(England)Order2015 

Thank you for taking the time to read this article, we look forward to hearing from you so please do not hesitate to get in touch.

Recommended Reading:

• House Extension design approach

• Maximising the view of your garden: Sliding vs Bi-fold glazing

We are always delighted to hear from you and to speak about your project