Side return extension in Merton

Deep precedent on the Wimbledon and South Wimbledon terraces; the planned Edwardian Article 4 streets and the Wimbledon conservation areas need a full application. Side extensions have no permitted-development route inside a conservation area.

Deep precedent on the Wimbledon and South Wimbledon terraces; the John Innes Article 4 areas need a full application.

Where the stock is continuous terrace, side returns are a familiar and well-precedented project, judged on boundary wall height, neighbour daylight and roof junction detail. In the Article 4 planned streets, the local design guide sets detailed expectations for side and rear extensions, roofs, walls, doors and windows — so the application is not a blank canvas. Outside those pockets, ordinary PD tests still apply to pure side infills that stay within the limits.

Under permitted development, side extensions (GPDO Class A) must be single storey, no more than 4m high and no wider than half the original house — but side extensions are excluded from PD entirely in conservation areas. Wrap-around schemes combining side and rear elements usually exceed PD limits and need full permission everywhere.

In practice, most London side returns proceed by full householder application. The good news is the precedent base: on streets of identical terraces, a consented side return three doors down is the strongest evidence your scheme can cite. Officers focus on the boundary wall height, neighbour daylight and the junction with the host roof.