Planning permission for extensions

Planning permission for an extension can follow one of several routes: permitted development (no application, ideally confirmed with a lawful development certificate), prior approval for a larger single-storey rear extension in England, or a full householder planning application.

Choosing the right route saves time and money. We check your property's history, any conservation area or Article 4 restrictions and the limits that apply, then prepare and submit the application and deal with the council until a decision is issued.

What is included

• Planning history and constraints check for your address
• Route recommendation in writing
• Application forms, plans and supporting statements
• Submission and fee payment guidance
• Liaison with the planning officer
• Advice if conditions are attached or changes are requested

Who it suits

• Anyone unsure whether their extension needs permission
• Projects in conservation areas or with previous refusals
• Homeowners who would rather not deal with the council themselves

Design advice

A lawful development certificate is not compulsory for permitted development, but it is the cleanest proof that the extension was lawful when you come to sell. We usually recommend one.

How much does it cost?

National guide prices including VAT at 20%. Your area page shows prices adjusted for your region.

Our handling fee only. Council fees are extra: in England from 1 April 2026 a householder application is £548, a lawful development certificate for a proposed extension £274 and a larger home extension prior approval £249. Drawings are priced separately.

Planning rules across the UK

England

In England the main routes are permitted development (ideally confirmed with a lawful development certificate, £274), larger home extension prior approval (£249, 42 days) and a householder planning application (£548, normally 8 weeks), with council fees as set from 1 April 2026.

Wales

In Wales the routes are permitted development (a lawful development certificate is available), or a householder planning application to the council. Wales has no prior approval scheme for larger rear extensions, and fees are set by the Welsh Government.

Scotland

In Scotland the questions are whether the extension falls within householder permitted development (Classes 1A to 1D) or needs planning permission from the council, and the building warrant, which is required before construction begins and is followed by a completion certificate.

Northern Ireland

In Northern Ireland we check the permitted development limits for your house type and, where needed, apply to your council for planning permission, then submit full plans or a building notice to council building control.

Building regulations and neighbours

Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.

In England and Wales, if the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations. Scotland and Northern Ireland have no Party Wall Act.

Questions about planning permission for extensions