Rear extensions in Richmond upon Thames depend on the house. Typical homes here: Georgian and Regency houses on Richmond Hill, in Petersham and around Richmond Green; Victorian terraces in Twickenham, St Margarets, Mortlake and East Sheen. Designations to check first: Conservation areas; Article 4 directions; Thames flood zones. Applications are decided by London Borough of Richmond upon Thames and the Richmond upon Thames Local Plan.
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 Richmond upon Thames
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 Richmond upon Thames are listed below, taken from our Richmond upon Thames area page. Each one is a reason to confirm the address on Richmond upon Thames' constraints map before relying on permitted development.
- Conservation areas. Richmond has 85 conservation areas, covering a large share of the borough's housing. Source
- Article 4 directions. Many Richmond conservation areas carry Article 4 directions removing permitted development for front elevations, windows, porches, boundary walls and hardstandings. Source
- Thames flood zones. Low-lying land at Barnes, Mortlake, Kew, Twickenham riverside, Teddington and Hampton falls within Flood Zones 2 and 3. Source
- Metropolitan Open Land and Royal Parks. Richmond Park, Bushy Park, Kew Gardens (a World Heritage Site) and Ham Lands are Metropolitan Open Land or protected landscapes.
- Listed buildings. The borough has a high number of listed buildings, particularly around Richmond Green, Richmond Hill, Petersham, Twickenham riverside and Hampton.
What Richmond upon Thames planning officers look for
Rear extensions deeper than neighbouring precedent, roof extensions that are not clearly subordinate, and front dormers are common refusal reasons. In conservation areas expect detailed comments on windows, brick and rainwater goods. Pre-application advice is available for a fee and, in our experience, is worth it for anything in a conservation area or on the river.
Fees and timelines
Richmond upon Thames 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 Richmond upon Thames: planning: the council's own constraints map, validation checklist and pre-application service.
