Side extensions in Ealing depend on the house. Typical homes here: Edwardian semi-detached and detached houses in Ealing, Ealing Common, Northfields and Pitshanger; Victorian terraces in Acton, Hanwell, West Ealing and South Ealing. Designations to check first: Conservation areas; Article 4 directions in garden suburbs and estates; Flood risk: River Brent and Grand Union Canal. Applications are decided by London Borough of Ealing and the Ealing Development Strategy 2026 and Development Management DPD.
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 Ealing
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 Ealing are listed below, taken from our Ealing area page. Each one is a reason to confirm the address on Ealing's constraints map before relying on permitted development.
- Conservation areas. Ealing has numerous conservation areas, including Brentham Garden Suburb, Bedford Park (shared with Hounslow), Ealing Common, Ealing Town Centre, Hanger Hill Garden Estate, Haven Green and Hanwell Village Green. Source
- Article 4 directions in garden suburbs and estates. Brentham Garden Suburb, Bedford Park and the Hanger Hill Garden Estate, among others, have Article 4 directions removing permitted development for external alterations, so most changes need planning permission. Source
- Flood risk: River Brent and Grand Union Canal. The River Brent through Hanwell, Perivale and Greenford, and the Grand Union Canal through Southall and Alperton borders, place some streets in Flood Zones 2 and 3. Source
- Green Belt and Metropolitan Open Land. Northolt, Horsenden Hill, Perivale Park and the Brent River Park include Green Belt and Metropolitan Open Land. Source
- HMO Article 4 direction. Ealing may operate an Article 4 direction requiring planning permission to convert a house into a small house in multiple occupation (HMO). Source
What Ealing planning officers look for
Ealing officers apply the residential extensions guidance closely. Common refusal reasons are two-storey side extensions without a set-back from the front wall, rear extensions that fail the 45-degree test, and roof extensions in conservation areas that do not match the existing pattern. On the 1930s semis of Greenford and Perivale, hip-to-gable lofts and 4–6 m rear extensions are often possible under permitted development, but where planning permission is needed the council's guidance says a hip-to-gable on a semi will normally be refused. The council offers a paid pre-application service, which we recommend for Brentham, Bedford Park and Hanger Hill.
Fees and timelines
Ealing 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 Ealing: planning: the council's own constraints map, validation checklist and pre-application service.
