Rear extensions in Lambeth depend on the house. Typical homes here: Georgian and early Victorian terraces in Kennington, Stockwell and Clapham Old Town; Victorian terraces in Brixton, Herne Hill, Clapham and Tulse Hill. Designations to check first: Conservation areas; Article 4 directions; Thames flood zones. Applications are decided by London Borough of Lambeth and the Lambeth Local Plan 2021.
The permitted development rules for rear extensions
On a house, a single-storey rear extension is permitted development if it projects no more than 3 m from the original rear wall on a terraced or semi-detached house, or 4 m on a detached house, is no higher than 4 m, has eaves no higher than 3 m where it comes within 2 m of a boundary, and uses materials similar in appearance to the house. The larger home extension route allows 6 m or 8 m through a 42-day prior approval, where the council consults the neighbours.
Flats and maisonettes have no householder permitted development rights, so any rear extension to a flat needs planning permission. Previous extensions count against the allowance, and the larger home extension route is not available in conservation areas.
What changes in Lambeth
In a conservation area a single-storey rear extension can still be permitted development within the 3 m or 4 m limit, but cladding it in materials that differ from the house is not, and the 6 m and 8 m prior approval route is closed.
The local constraints that most often decide the route in Lambeth are listed below, taken from our Lambeth area page. Each one is a reason to confirm the address on Lambeth's constraints map before relying on permitted development.
- Conservation areas. Lambeth has numerous conservation areas covering much of Kennington, Stockwell, Clapham, Brixton, Herne Hill and Streatham. Source
- Article 4 directions. Lambeth has Article 4 directions in a number of conservation areas removing permitted development for front alterations and boundary treatments, and a Class MA Article 4 covering Waterloo, Vauxhall and other central and town-centre locations that removes the commercial-to-residential prior approval route.
- Thames flood zones. Waterloo, Vauxhall, Nine Elms and the riverside at Lambeth fall within Flood Zones 2 and 3, protected by the Thames Barrier and river walls. Source
- Listed buildings and the Kennington and Clapham set pieces. Kennington, Clapham Old Town, Stockwell and the Vauxhall riverside contain many listed Georgian and Victorian houses and terraces.
- Metropolitan Open Land. Clapham Common, Brockwell Park, Streatham Common and Norwood Park are Metropolitan Open Land.
What Lambeth planning officers look for
Rear extensions deeper than neighbouring precedent, side returns that breach the 45-degree rule to the neighbour's rear window and roof extensions in conservation areas are the common refusal reasons. Pre-application advice is available for a fee, and Lambeth's decision times can stretch beyond the statutory period at busy times.
Fees and timelines
Lambeth decides a householder application or a Lawful Development Certificate within 8 weeks of validation. The council fee is £528 for a householder application and £264 for a Lawful Development Certificate (England, from 1 April 2025; verify before applying).
Our own fee is fixed once quoted. The quote tool gives an indicative figure in minutes and a written quote follows within 24 hours.
Primary sources
- The Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2: the permitted development limits quoted above.
- Planning Portal: do you need permission: the national guidance and the application service every council accepts.
- London Borough of Lambeth: planning: the council's own constraints map, validation checklist and pre-application service.
