Does my extension need planning permission in South East London or Kent?

The honest answer is that it depends, and the difference between permitted development and a full planning application changes both your timeline and your budget. It is worth understanding before you commission drawings.

Permitted development, in plain terms

Permitted development is a set of national rights that let you build certain things without a planning application. Most single storey rear extensions on a house fall inside it, provided they stay within the size, height and material limits set out in the legislation. Loft conversions have their own volume allowances.

What commonly cancels those rights

• Flats and maisonettes have no permitted development rights for extensions at all.
• Conservation areas and listed buildings are heavily restricted. Parts of Sevenoaks, Tunbridge Wells and Chislehurst have designated areas.
• An Article 4 direction can remove permitted development rights for a specific street or estate. Your council’s planning pages will say.
• Previous extensions count towards your allowance, even if a previous owner built them.

Building regulations are separate

This catches people out. Planning permission and building regulations are two different things. Even work that needs no planning application still needs building regulations approval for structure, insulation, fire safety, drainage and electrics. Skipping it causes real problems when you come to sell.

The practical route

Check your council’s planning portal first, then consider a lawful development certificate. It is not compulsory, but it is a formal confirmation from the council that your project is permitted development, and it removes any argument later. Buyers’ solicitors ask for it.

If you are planning an extension or loft conversion and you are not sure which side of the line you are on, talk to us before you spend anything. We will tell you what we think applies and where you need professional advice we do not provide.