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Ealing · Two-storey extension · Checked 30 Oct 2026

Do I need planning permission for a two-storey extension in Ealing?

Short answer

Usually yes. A two-storey rear extension is permitted development only if it is no more than 3 m deep and at least 7 m from the rear boundary, which most London plots cannot meet, so a householder planning application is the normal route. In a conservation area a two-storey extension always needs planning permission. Ealing has conservation areas and Article 4 directions that remove some permitted development rights, so we check the address on Ealing's constraints map before advising a route.

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Two-storey 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 two-storey extensions

A two-storey rear extension is permitted development only within tight limits: no more than 3 m deep, at least 7 m from the rear boundary, no higher than the existing house, eaves matching the existing eaves, materials similar in appearance, and any upper-floor side window obscure-glazed and non-opening below 1.7 m.

Most two-storey extensions exceed one of those limits, most often the 7 m rear boundary rule on London plots, so the usual route is a householder planning application. Flats have no permitted development rights.

What changes in Ealing

Extensions of more than one storey are not permitted development in a conservation area, so planning permission is always needed there.

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

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. Decisions often run past 8 weeks; allow 10–14 weeks.

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).

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Primary sources

02Questions

Two-storey extensions in Ealing: common questions

What is the 45-degree test?

A line drawn at 45 degrees from the centre of the neighbour's nearest habitable room window. If your first-floor extension crosses it, officers treat it as harming their daylight and will ask for the depth to be reduced or the extension set in from the boundary. We plot it on every two-storey scheme before submission.

Can the ground floor go deeper than the first floor?

Yes, and it usually should. A common approach is a 4 m ground floor with a 3 m first floor set 1 m in from the shared boundary, which keeps the daylight line clear while giving a full-width kitchen below.

Does the roof have to match?

Councils expect the extension roof to follow the form of the main roof, for example a hipped roof on a 1930s semi, and to sit below the existing ridge. A flat-roofed first floor is normally refused on a pitched-roof house.

How long does Ealing take to decide?

The statutory period is 8 weeks from validation for both a householder application and a Lawful Development Certificate, and 42 days for a larger home extension prior approval. Decisions often run past 8 weeks; allow 10–14 weeks.

03Examples

Example projects that face these questions

Proposed ground floor plan of a two-storey rear extension and side infill to a 1930s semi in EalingExample project
Two-storey extensionNorthfields, Ealing

Two-Storey Extension in Northfields, Ealing

Two-storey rear extension with a single-storey side infill to a 1930s semi-detached house, adding a kitchen-dining room, a fourth bedroom and a family bathroom.

Typical route: Householder planning application for both storeys in one submission

Next step

Planning a two-storey extension in Ealing?

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