Do I Need Planning Permission for an Extension?

Permitted development

Permitted development rights let you carry out certain projects without a full planning application. This often covers single-storey rear extensions within set size and height limits, modest side extensions, and many loft conversions.

The exact limits depend on your property and whether previous extensions have used up your allowance, so it always pays to confirm rather than assume.

When you do need permission

You’ll usually need full planning permission for larger or double-storey extensions beyond the permitted limits, anything that extends towards a road at the front, and work on flats or maisonettes.

Listed buildings and homes in conservation areas have tighter rules, and permitted development rights are sometimes removed by the local authority — another reason to check first.

Building regulations are separate

Whether or not you need planning permission, almost all extensions must comply with building regulations — these cover structure, insulation, fire safety, drainage and more, and are signed off by building control.

We advise on planning permission, build to current building regulations, and coordinate the necessary inspections through to sign-off, so you don’t have to navigate it alone.