Do you need planning permission for an extension in Manchester?

Most homeowners assume every extension needs planning permission. Many don’t — and knowing the difference can save you months. Here’s the plain-English version for Greater Manchester.

Permitted development: what you can build without an application

Most houses (not flats) come with permitted development rights — a national allowance to extend without a full planning application, provided you stay inside the limits. For a typical semi-detached house the key ones are:

• Single storey rear extensions up to 3 metres deep (6 metres under the larger home extension scheme, with prior approval).
• Maximum height of 4 metres for a single storey rear extension.
• Materials that are similar in appearance to the existing house.
• No more than half the garden covered by extensions and outbuildings.
• Side extensions limited to single storey and half the width of the original house.

When you definitely need planning permission

• Double storey rear extensions beyond 3 metres, or any two-storey work near a boundary.
• Homes in conservation areas — parts of Didsbury, Chorlton, Worsley, Alderley Edge and Prestbury are covered.
• Flats and maisonettes — no permitted development rights at all.
• Houses where rights were removed by the original planning consent (common on newer estates).
• Wraparound extensions — the combination usually takes you outside the rules even when each part alone would pass.

The certificate most people skip — and shouldn’t

Even when your extension is permitted development, get a Lawful Development Certificate from the council. It costs a few hundred pounds, takes about eight weeks, and is the piece of paper your solicitor will want when you sell. Building without one isn’t illegal — but proving compliance years later, without it, is painful.

Don’t forget building regulations

Planning permission and building regulations are separate. Every extension needs building regulations approval — structure, insulation, drainage, electrics, fire safety — regardless of whether planning permission was required. Our projects are inspected and signed off at each stage, and you receive the completion certificate at handover.

How we handle it

On a design-and-build contract, our design partners assess your permitted development position at the first consultation, prepare the drawings, and submit whichever route applies — full application, prior approval or lawful development certificate — while the build programme is planned around the decision dates. One less thing for you to project-manage.