A side extension in Redbridge usually starts from one of two houses. On the 1930s semis of Gants Hill, Barkingside, Newbury Park and Clayhall, the gap beside the house, or the garage in it, is the obvious place to add a bedroom or kitchen. On the Victorian and Edwardian terraces of Ilford, Seven Kings and Goodmayes, an end-of-terrace house with a road or path beside it has a side that faces the street. The council's Housing Design guidance treats those two situations differently, so the first job is to read the plot, then the set-backs.
The permitted development rules for side extensions
A single-storey side extension is permitted development on a house if it is no wider than half the width of the original house, no higher than 4 m, with eaves no higher than 3 m where it comes within 2 m of a boundary, and finished in materials similar in appearance to the house.
Anything wider than half the original house, any two-storey side extension, and any side extension on a flat needs planning permission. Garage conversions that keep the walls are usually permitted development; extending beyond them is assessed as a side extension.
What changes in Redbridge
Side extensions are not permitted development in a conservation area at all, so there a planning application is always required.
The local constraints that most often decide the route in Redbridge are listed below, taken from our Redbridge area page. Each one is a reason to confirm the address on Redbridge's constraints map before relying on permitted development.
- Green Belt. The north and east of the borough, including Hainault Forest, Fairlop Waters, Claybury and land around Woodford Bridge, is Green Belt. Source
- Conservation areas. Redbridge's conservation areas are concentrated in Wanstead and Woodford, including Wanstead Village, Woodford Bridge and Monkhams. Source
- Article 4 direction on HMOs. Redbridge has used an Article 4 direction to remove permitted development for converting a house into a small house in multiple occupation (C3 to C4), so HMO conversions normally need planning permission. Source
- River Roding flood risk. The River Roding runs the length of the borough from Woodford Bridge through Wanstead and Ilford, and land alongside it sits in Flood Zones 2 and 3. Source
- Epping Forest land. Wanstead Flats, Wanstead Park and the Forest land in Snaresbrook and Woodford are protected open space within the Epping Forest Special Area of Conservation. Source
- Listed buildings. Wanstead, Woodford and the older centres of Ilford and Barkingside contain listed houses and churches. Source
What Redbridge's Housing Design guidance asks of a side extension
Local Plan policy LP30 (Household Extensions) supports householder development that is subordinate to the existing building in size, scale or height, that maintains adequate spacing between buildings, and that respects the council's householder design guidance. That guidance is now the Housing Design Supplementary Planning Document, adopted in September 2019, which replaced the 2012 Householder Design Guide that the Local Plan still names. It is a material consideration in deciding applications.
For a single-storey side extension the SPD says the width should be no more than half the width of the host house and the depth should not exceed that of the house. The roof should match the house in design and angle, and a separate front entrance door in the side extension is not acceptable. For a two-storey or first-floor side extension the SPD adds that the width again should not exceed half the house, the ridge should be set down at least 0.5 m below the main ridge, and the first-floor element should be set back at least 0.5 m from the main front elevation. Where the original roof has been changed from hip to gable, it says a hipped roof to the side extension is likely to be required.
Boundaries, angled plots and corner houses
The SPD says no part of a side extension may cross the boundary line unless it forms a party wall, and the roof of a side extension must not be used as a balcony. Where a shared boundary runs at an angle, the side wall should be parallel to the original house and staggered or stepped, not follow the boundary, and its Figure 10 notes that proposals following an angled boundary will generally be refused. On sites of an open character, it asks for the extension to be set 1 m from the site boundary.
For a corner plot or end-of-terrace house with a road or footpath alongside, the SPD says a side extension becomes more visible from the street. Where the site is open in character the extension should be set in 1 m from the side boundary, and the council may refuse a bulky extension that is not subordinate and presents a large blank flank wall to the side street. On a two-storey side and rear scheme, the first-floor part of the rear extension should be set in 0.5 m from the side elevation to avoid that blank wall.
What Redbridge planning officers look for
Redbridge officers assess householder applications against the Local Plan and the council's supplementary guidance on residential extensions. On the 1930s semis that dominate the borough they look for two-storey side extensions set back from the front wall and below the main ridge, a gap kept to the side boundary so the pair does not read as a terrace, rear extensions that pass the 45-degree test to the neighbour's nearest habitable window, and hipped roofs kept where a gable would unbalance the pair. Common refusal reasons are full-width box dormers, side extensions that create a terracing effect, and roof extensions on front slopes in conservation areas. Outside conservation areas, hip-to-gable and rear-dormer lofts within 50 m³ on a semi are routinely lawful and we secure a Lawful Development Certificate as proof.
Fees and timelines
Redbridge 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
- London Borough of Redbridge: Housing Design Supplementary Planning Document (adopted September 2019)
- London Borough of Redbridge: Redbridge Local Plan 2015-2030 (adopted 2018)
- 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 Redbridge: planning: the council's own constraints map, validation checklist and pre-application service.
