Rear extensions in Greenwich depend on the house. Typical homes here: Georgian and early Victorian terraces and villas in West Greenwich, Blackheath and Greenwich town centre; Victorian terraces in Charlton, Plumstead, Westcombe Park and Woolwich. Designations to check first: Conservation areas; Article 4 directions; Thames flood risk. Applications are decided by Royal Borough of Greenwich and the Royal Greenwich Local Plan: Core Strategy with Detailed Policies (2014).
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 Greenwich
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 Greenwich are listed below, taken from our Greenwich area page. Each one is a reason to confirm the address on Greenwich's constraints map before relying on permitted development.
- Conservation areas. Royal Greenwich has numerous conservation areas, including West Greenwich, Blackheath, Blackheath Park, Westcombe Park, Charlton Village, Eltham Palace, the Progress Estate and Woolwich Common. Source
- Article 4 directions. Several conservation areas, notably the Progress Estate in Eltham and parts of Blackheath, have Article 4 directions removing permitted development for external alterations, so most changes need planning permission. Source
- Thames flood risk. The riverside from Greenwich Peninsula through Charlton, Woolwich and Thamesmead lies in Flood Zones 2 and 3 behind the Thames Barrier and river defences. Source
- Metropolitan Open Land and Royal Parks. Blackheath, Greenwich Park, Woolwich Common, Oxleas Wood and Shooters Hill are Metropolitan Open Land or Royal Park. Source
- Listed buildings. Greenwich town centre, Blackheath and Eltham contain a high concentration of listed buildings. Source
What Greenwich planning officers look for
Common refusal reasons are rear extensions that breach the 45-degree line or exceed the neighbour's depth, roof extensions in conservation areas that break the roofline of a terrace, front dormers, and alterations to Span houses or the Progress Estate that depart from the original detailing. The council offers a paid pre-application service, which we recommend in the World Heritage Site buffer zone and Blackheath. Decisions often run past 8 weeks; allow 10–14 weeks.
Fees and timelines
Greenwich 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.
- Royal Borough of Greenwich: planning: the council's own constraints map, validation checklist and pre-application service.
