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Enfield · Rear extension · Checked 30 Oct 2026

Do I need planning permission for a rear extension in Enfield?

Short answer

Often not. A single-storey rear extension up to 3 m deep on a terraced or semi-detached house, or 4 m on a detached house, and no higher than 4 m is normally permitted development; anything deeper or taller, or any extension to a flat, needs planning permission. In a conservation area the 3 m or 4 m limit still applies, but the larger 6 m and 8 m route does not. Enfield has conservation areas and Article 4 directions that remove some permitted development rights, so we check the address on Enfield's constraints map before advising a route.

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Rear extensions in Enfield depend on the house. Typical homes here: 1930s semi-detached houses in Southgate, Oakwood, Winchmore Hill, Enfield Town suburbs and Edmonton; Victorian and Edwardian terraces in Palmers Green, Bowes Park, Edmonton and Ponders End. Designations to check first: Green Belt; Lee Valley flood risk; Conservation areas. Applications are decided by London Borough of Enfield and the Enfield Local Plan (Core Strategy 2010 and Development Management Document 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 Enfield

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 Enfield are listed below, taken from our Enfield area page. Each one is a reason to confirm the address on Enfield's constraints map before relying on permitted development.

  • Green Belt. Enfield has one of the largest Green Belt areas of any London borough, covering Crews Hill, Botany Bay, Forty Hill, Whitewebbs, Trent Park and the fringes of Enfield Chase. Source
  • Lee Valley flood risk. The eastern edge of the borough along the River Lee and its tributaries (Salmons Brook, Pymmes Brook, Turkey Brook) sits in Flood Zones 2 and 3, affecting parts of Edmonton, Ponders End, Enfield Lock and Brimsdown. Source
  • Conservation areas. Enfield has numerous conservation areas, including Enfield Town, Forty Hill, Bush Hill Park, Winchmore Hill Green, Southgate Green, the Lakes Estate and Trent Park. Source
  • Article 4 directions. Several Enfield conservation areas, including Bush Hill Park and the Lakes Estate, have Article 4 directions removing permitted development for front alterations, boundary walls and some roof works. Source

What Enfield planning officers look for

Enfield officers are, in our experience, reasonable on suburban householder work but firm on set-backs and the 45-degree test. Common refusal reasons are two-storey side extensions flush with the front wall that create a terracing effect, rear extensions deeper than the neighbour's, front dormers, and box dormers that wrap the hip. Hip-to-gable lofts and 4–6 m rear extensions on ordinary 1930s semis are usually accepted. The council offers a paid pre-application service and decisions often run beyond 8 weeks, so allow 10–14 weeks.

Fees and timelines

Enfield 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

Rear extensions in Enfield: common questions

How deep can I extend without planning permission?

Three metres from the original rear wall on a terraced or semi-detached house and four metres on a detached house, under Class A permitted development. Six or eight metres is possible through the larger home extension prior approval, a 42-day process with a £120 fee, outside conservation areas.

Do I need a Lawful Development Certificate if the extension is permitted development?

Not legally, but we recommend one. It is the council's formal confirmation that the extension is lawful, which lenders, buyers and solicitors routinely ask for. The fee is £264 and the decision takes up to 8 weeks.

What if my neighbour has already extended?

Their extension does not change your rights, but it does shape what the council will accept if you need planning permission: officers compare depth and height against the neighbouring extension and apply the 45-degree daylight test from the nearest habitable window.

How long does Enfield 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. The council offers a paid pre-application service and decisions often run beyond 8 weeks, so allow 10–14 weeks.

03Examples

Example projects that face these questions

Proposed ground floor plan of a 3.5 m deep rear extension to a Victorian terrace in Highbury, IslingtonExample project
Rear extensionHighbury, Islington

Rear Extension in Highbury, Islington

Full-width single-storey rear extension, 3.5 m deep with three rooflights, to a Victorian terrace in a Highbury conservation area, creating an open kitchen and dining room.

Typical route: Householder planning application in a conservation area

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Planning a rear extension in Enfield?

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