What Is Permitted Development?
Permitted development (PD) rights allow certain types of building work to proceed without a full planning application, provided the work stays within defined limits. These rights are granted automatically under the Town and Country Planning (General Permitted Development) (England) Order 2015. For houses — not flats or maisonettes — permitted development rights cover rear extensions, loft conversions, and certain outbuildings, subject to specific size and design conditions.
Rear Extensions Under Permitted Development
For a single-storey rear extension, permitted development rights allow up to 3 metres beyond the original rear wall for a terrace or semi-detached house, and up to 4 metres for a detached house. Under the Larger Home Extension Scheme, single-storey rear extensions can extend to 6 metres for terraced or semi-detached houses, and up to 8 metres for detached houses — subject to a prior approval application.
Side Extensions
Side extensions are generally more restricted: a maximum of 50% of the width of the original house, single storey only in most cases, and not closer to the highway than the original house. Side extensions in many parts of London also fall within Article 4 directions, which remove permitted development rights entirely.
Double-Storey Extensions
Double-storey rear extensions must be no closer than 7 metres to the rear boundary, must not exceed the existing roof ridge height, and the roof pitch must match the main house where possible. In practice, many double-storey extensions in London require full planning permission, particularly on smaller plots.
What Removes Permitted Development Rights?
Article 4 Directions allow local planning authorities to remove permitted development rights in specific areas. This is common in conservation areas, around listed buildings, and in some residential neighbourhoods. Previous extensions count against the total permitted. Conditions on original planning permissions may restrict PD rights. Flats and maisonettes do not have PD rights at all.
How to Check Whether You Need Planning Permission
Check whether your property is in a conservation area or Article 4 zone. Review the planning history for any conditions. Submit a Certificate of Lawful Development application for formal written confirmation. At RCB Design & Build, we help clients understand what is achievable under permitted development before any design work begins.
Thinking about extending your home in London? Contact RCB Design & Build: 07359 872594 | contact@rcbgroup.co.uk