Rear extension in Hammersmith and Fulham

Often not, for houses outside the conservation areas — a single-storey rear extension within the standard 3m (attached) or 4m (detached) limits can proceed under permitted development, and the larger 6m/8m prior-approval route is available on unconstrained houses too. Inside a conservation area, side and two-storey rear additions lose permitted development, but a modest single-storey rear can still qualify unless a direction or listed status says otherwise. Flats have no permitted development rights at all, and tenure is the first check in a borough with a high share of flats and maisonettes.

Outside the conservation areas many terraces keep PD rights; inside them, match the established depth and materials.

Hammersmith and Fulham is prime west-London extension territory: long Victorian and Edwardian terrace runs around Brook Green, Bradmore and Ravenscourt, the denser Fulham and Brackenbury streets, and the larger mansion stock toward Hurlingham and Parson's Green. Conservation areas cover much of that period grain, so roof form, materials and rear design are scrutinised on the protected streets, while outside them the usual rear-extension and prior-approval routes still do real work. Officers read a scheme against the established projection and materials on your own row more than against any borough-wide depth rule.

Permitted development (GPDO Class A) covers single-storey rear extensions up to 3m beyond the original rear wall on attached houses and 4m on detached, with a maximum height of 4m. The 'larger home extension' route extends this to 6m/8m through prior approval with neighbour consultation — but that larger route is not available in conservation areas.

In conservation areas, the basic 3m/4m single-storey rear PD allowance usually survives — what conservation-area status removes is side extensions and two-storey rear extensions. An Article 4 direction can remove more, but Camden's directions in Hampstead and Belsize target front-and-side appearance (solar panels, window changes, boundary treatments), not the single-storey rear allowance. Flats have no PD rights at all. Two-storey rear extensions in conservation areas always need full permission.

Practical rule across London: check the address first. If a conservation area or Article 4 direction applies, budget for a full householder application decided on design, neighbour daylight (the 45-degree test) and materials.