Garden rooms and outbuildings in Bexley depend on the house. Typical homes here: 1930s semi-detached houses in Bexleyheath, Welling, Sidcup, Blackfen and Barnehurst; Victorian and Edwardian terraces in Erith, Belvedere and Crayford. Designations to check first: Conservation areas; Thames and Cray flood risk; Green Belt and Metropolitan Open Land. Applications are decided by London Borough of Bexley and the Bexley Local Plan (2023).
The permitted development rules for garden rooms and outbuildings
An outbuilding is permitted development on a house if it is single storey, no higher than 2.5 m where it comes within 2 m of a boundary, otherwise no higher than 4 m with a dual-pitched roof or 3 m with any other roof, sits behind the front wall of the house, covers together with other outbuildings no more than half the land around the original house, and is used for purposes incidental to the house rather than as a bedroom or self-contained flat.
Anything used for sleeping or as a separate dwelling needs planning permission regardless of size. Flats have no permitted development rights for outbuildings, and listed buildings need listed building consent.
What changes in Bexley
In a conservation area an outbuilding is still permitted development behind the house, but not to the side of it, and the same height limits apply.
The local constraints that most often decide the route in Bexley are listed below, taken from our Bexley area page. Each one is a reason to confirm the address on Bexley's constraints map before relying on permitted development.
- Conservation areas. Bexley has a modest number of conservation areas, including Bexley Village (Old Bexley), and several historic centres and estates. Source
- Thames and Cray flood risk. Erith, Belvedere, Thamesmead, Slade Green and the Crayford Marshes lie in Flood Zones 2 and 3 behind the Thames defences; the River Cray and Shuttle also carry fluvial flood risk. Source
- Green Belt and Metropolitan Open Land. Foots Cray Meadows, the Cray valley, Lesnes Abbey Woods and Crayford Marshes include Green Belt and Metropolitan Open Land. Source
- Article 4 directions. We are not aware of a borough-wide Article 4 direction removing householder permitted development in Bexley, but directions may exist for specific conservation areas or for houses in multiple occupation. Source
What Bexley planning officers look for
Front dormers and flat-roofed dormers that wrap the hip are the usual loft refusals. The council generally offers a paid pre-application service. Decision times are usually close to the statutory 8 weeks, though a formal extension of time is not unusual.
Fees and timelines
Bexley 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 Bexley: planning: the council's own constraints map, validation checklist and pre-application service.
