Planning permission

When you might need planning permission

You will need planning permission if you want to:

• build something new,
• make a major change to your building, such as an extension,
• change the use of your building.

We recommend that you get pre-application advice. We can give you an idea of whether your proposal will be approved or not. The service can save you time and money. To find out more see our pre-application advice service page.

If you do not want pre-application advice, you should check if you need planning permission. If needed, it should be granted before any work begins. You can check if you need planning permission by going to the Planning Portal.

There are interactive guides and common project guides. They have planning and building rules you must follow.

If you want to help with extensions and home conversions, see the Residential Design Guide.

When you are ready to apply, see our apply for planning permission page.

Building regulations permission

Most extensions and alterations need a building regulations' application. Building Control ensures that building works meet set standards for:

• health and safety of people in and around buildings
• conservation of fuel and power, and
• accessibility.

Find out more information on our Building Control page. 

When you may not need planning permission

Some developments do not need planning permission. For more information, see our permitted development page.

If your project does not need planning permission, apply for a certificate of lawful proposed development (CLPD). A CLPD confirms whether a development is lawful for planning. It can be for an existing or proposed development. For more information, see our CLPD page.

You may need to get prior approval before starting any work. For more information, see our prior approval for extensions and conversions page.

The Planning Portal has guidance on plans for common projects including:

• loft conversions and
• small, single-storey house extensions.

See The Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended). It provides the main order. It lists development classes with an automatic grant of planning permission.

It depends on no restrictive condition being attached. Or, that the development is exempt from the permitted development right.

Where planning permission will not be granted

Some restrictions can vary depending on:

• the site constraints or property you live in
• whether the building is a listed building or not
• whether your property is in a conservation area.

For more information see the following pages:

• Conservation areas
• Listed buildings
• Article 4 directions
• Harrow's protected trees

Planning permission frequently asked questions