Planning permission by project
Whether you need planning permission depends on the project and the address, in that order. Each guide below sets out the permitted-development limits from the GPDO, the realistic cost range, the timeline and what actually gets approved — then the address check tells you which of it survives the constraints on your own property.
The default London move: kitchen-diner across the back.
Single-storey rear depth — attached house: 3m beyond the original rear wall
Rear extension planning rules & costs →Infilling the Victorian alley for a full-width kitchen.
Storeys: Single storey only
Side return extension planning rules & costs →A bedroom and bathroom in the roof — the value workhorse.
Roof volume added — terraced house: Up to 40m³
Loft conversion planning rules & costs →The biggest space gain — and the hardest consent in London.
Permitted development: None in practice — assume a full planning application
Basement extension planning rules & costs →Office, studio or gym at the end of the garden — often no planning needed.
Maximum height within 2m of a boundary: 2.5m
Garden room planning rules & costs →