Rear extensions in Hammersmith and Fulham depend on the house. Typical homes here: Victorian terraces in Fulham, Parsons Green, Munster Village and the Peterborough Estate; Victorian and Edwardian terraces in Brackenbury Village, Brook Green, Ravenscourt Park and Askew. Designations to check first: Conservation areas and Article 4 directions; Basement policy; Thames flood risk. Applications are decided by London Borough of Hammersmith and Fulham and the Hammersmith and Fulham Local Plan (2018).
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 Hammersmith and Fulham
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 Hammersmith and Fulham are listed below, taken from our Hammersmith and Fulham area page. Each one is a reason to confirm the address on Hammersmith and Fulham's constraints map before relying on permitted development.
- Conservation areas and Article 4 directions. Hammersmith and Fulham has numerous conservation areas covering much of its Victorian housing, including the Peterborough Estate, Parsons Green, Brackenbury, Brook Green, Ravenscourt and Starch Green, and Hammersmith Mall. Source
- Basement policy. The Local Plan restricts basements to a single storey beneath the house and limits how far they can extend under the garden, and requires a construction method statement and flood risk and structural assessments. Source
- Thames flood risk. Much of Fulham and the Hammersmith riverside lies in Flood Zones 2 and 3 behind the Thames defences. Source
- Listed buildings. Hammersmith Mall, Brook Green and parts of Fulham contain listed houses and terraces. Source
What Hammersmith and Fulham planning officers look for
Hammersmith and Fulham officers apply the Planning Guidance SPD closely and are protective of terrace rear elevations and rooflines. Common refusal reasons are rear extensions deeper or taller than the guidance allows relative to neighbours, full-width box dormers, mansards on terraces where none exist, and front-facing changes in Article 4 areas. Rear dormers and side-return infills designed to the guidance are usually accepted. The council offers a paid pre-application service, which we recommend for anything in a conservation area or involving a basement.
Fees and timelines
Hammersmith and Fulham 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 Hammersmith and Fulham: planning: the council's own constraints map, validation checklist and pre-application service.
