Do I need planning permission?
The first question of every project — and how to answer it for your exact address in ten seconds rather than three weeks.
The honest answer: it depends on your address, not just your project
Two identical extensions, two streets apart, can have different answers. One falls under permitted development and needs no application; the other sits inside a conservation area with an Article 4 direction and needs full planning permission. The project is the same — the address decides.
That is why generic advice disappoints. The useful question is not "do extensions need permission?" but "does MY extension, at MY address, need permission?" — and that depends on the designations on your property.
Permitted development: the route most small projects use
The General Permitted Development Order grants automatic permission for many householder projects — extensions (Class A), roof additions (Class B), porches (Class D), outbuildings (Class E), driveways (Class F) — provided the work stays inside specific limits on size, height and siting.
But designations narrow these rights. Conservation areas (article 2(3) land) exclude some classes entirely; Article 4 directions can remove them street by street; flats and maisonettes have no householder permitted development rights at all.
The three checks that answer it
First: the designations on your property — conservation area, Article 4, listed building, flood zone, Green Belt, protected trees. Second: whether your project fits the permitted development limits for its class. Third: if an application is needed, the policies it will be judged against — national, strategic (in London) and your council's Local Plan.
Our free check answers the first in seconds from the official national index. The full report answers all three for your project, with every policy quoted verbatim and every claim linked to its official source.
General guidance ends here. Your property is specific.
The free check reads the designations on your exact property in seconds. The full report applies the policies above — and your council’s own Local Plan — to your project, with every quote verified against its source.