Rear extensions in Camden depend on the house. Typical homes here: Victorian terraces in Kentish Town, Camden Town, Gospel Oak, West Hampstead and Kilburn; Georgian terraces and squares in Bloomsbury, Fitzrovia, Somers Town and Hampstead village. Designations to check first: Conservation areas; Listed buildings; Article 4 directions. Applications are decided by London Borough of Camden and the Camden Local Plan (2017).
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 Camden
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 Camden are listed below, taken from our Camden area page. Each one is a reason to confirm the address on Camden's constraints map before relying on permitted development.
- Conservation areas. Camden has around 40 conservation areas covering a large share of its housing, including Hampstead, Belsize, Primrose Hill, Bloomsbury, Kentish Town, Fitzjohns/Netherhall and West End Green. Source
- Listed buildings. Camden has thousands of listed buildings, concentrated in Bloomsbury, Hampstead, Highgate and Primrose Hill. Source
- Article 4 directions. Camden has Article 4 directions in a number of conservation areas removing permitted development for front alterations and other works, and a direction restricting Class MA commercial-to-residential conversions in the Central Activities Zone and some town centres. Source
What Camden planning officers look for
Officers apply the CPG documents closely and pay particular attention to the uniformity of terrace rear elevations, the depth and height of rear extensions relative to neighbours, and roof additions in conservation areas, where a mansard or dormer is often only accepted if it matches an established pattern in the terrace. Front dormers and full-width box dormers are routinely refused. Camden offers a paid pre-application service and we strongly recommend it for anything in a conservation area or involving a basement. Decisions frequently run past the statutory 8 weeks; allow 12–16 weeks.
Fees and timelines
Camden 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 Camden: planning: the council's own constraints map, validation checklist and pre-application service.
