Do I Need Planning Permission for an Extension in Peterborough?

Planning permission is the question that sits at the front of every extension project — and the answer determines whether you can start building as soon as you’re ready or whether you need to wait two to three months for a decision from Peterborough City Council. The good news is that most single storey rear extensions across Peterborough fall within permitted development rights, meaning no planning application is needed. But the rules have conditions, and exceeding any one of them means you need formal approval.

This guide explains the permitted development rules, what you can build without applying, and when you need planning permission.

What Is Permitted Development?

Permitted development is a set of rights granted by the government that allow homeowners to carry out certain building work without applying for planning permission. These rights cover rear extensions, loft conversions, outbuildings, and porches — subject to specific conditions on size, height, and positioning.

The principle is that certain building work has limited impact on neighbours and the wider area, so individual assessment isn’t needed. As long as your project meets every condition, you can proceed. The key word is every — exceeding any single condition means you need a full application.

Rules for Single Storey Rear Extensions

For a single storey rear extension on a house in Peterborough, permitted development allows the following without planning permission.

Depth from the original rear wall — you can extend three metres from the original rear wall for an attached house. For a detached house, the allowance increases to four metres. These measurements are from the rear wall of the original house as first built or as it stood on 1 July 1948. Previous extensions count against this allowance.

Maximum height — the extension must not exceed four metres overall. Eaves height must not exceed three metres. Within two metres of a boundary, maximum eaves height drops to three metres.

Width — the extension must not extend beyond the side elevation of the original house.

Coverage — the extension together with other buildings must not cover more than half the area of land around the original house.

Materials — external materials must be similar in appearance to the existing house.

Position — no part of the extension can be forward of the principal elevation or side elevation facing a highway.

The Prior Approval Route

If you want to build deeper than the standard three or four metre allowance, the prior approval process allows single storey rear extensions up to six metres on attached houses or eight metres on detached. You notify Peterborough City Council, neighbours are consulted for 21 days, and if no valid objections are raised, approval is given.

Prior approval costs less than a full application — typically £96 — and the decision period is 42 days. It’s a useful route for extensions exceeding standard permitted development limits.

When Do You Need Full Planning Permission?

A full application is needed for double storey extensions of any size, single storey extensions exceeding prior approval limits, side extensions visible from a highway, extensions covering more than half the surrounding land, and work on listed buildings.

Properties with permitted development rights removed also need planning permission. Some newer developments across Peterborough — particularly recent estates — have conditions restricting permitted development. Check your property’s planning history if unsure.

Flats and maisonettes don’t benefit from permitted development rights for extensions.

The Application Process

Architectural drawings are prepared, the application is submitted with the fee, Peterborough City Council notifies neighbours and assesses the proposal against planning policies. The statutory determination period is eight weeks. Most single storey extension applications are approved where the design is proportionate and doesn’t harm neighbouring amenity.

Building Regulations

Planning permission and Building Regulations are separate. Even if your extension falls within permitted development, it must comply with Building Regulations covering structural integrity, insulation, ventilation, drainage, and electrical safety. Your builder arranges approval and coordinates inspections.

Conservation Areas

Peterborough has several conservation areas where permitted development rights may be more restricted. The Cathedral precinct, parts of the city centre, and certain village centres have designations that affect what can be built. Check before committing if your property is within a designated area.

Getting Started

Confirm whether your property has permitted development rights. Check for conditions on the original consent. If in doubt, request a Certificate of Lawful Development from Peterborough City Council for formal confirmation.

If you’re considering an extension and aren’t sure about planning, get in touch. We assess the planning position for every project before design work progresses, giving you clarity from the outset.