Rear extension in Ealing: Planning Permission Guide

Everything you need to know about building a rear extension in Ealing, including permitted development rules, typical costs, and which professionals you'll need.

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Rear extensions in Ealing at a glance

84%

approved

£258

application fee

8

weeks typical

Based on 840 decided applications in Ealing over 12 months (707 granted, 133 refused).

Ealing has over 30 conservation areas including Bedford Park — England's first garden suburb, with notoriously strict design controls — plus Ealing Common, Hanwell, Northfields, and Walpole. Listed building density is high in Bedford Park. Article 4 Directions restrict external changes in Bedford Park and other heritage areas, targeting window replacements and external alterations. The council's conservation enforcement is consistently active.

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Approval probability, 5 nearest comparables, refusal reasons — for your specific address.

Recent rear extension decisions in Ealing

The 5 most recent decided applications. Addresses redacted to postcode area.

Granted

Minor Material Amendment (S.73) to vary condition 2 (Approved Plans), for changes to the materials and appearance pursuant to planning pe…

W72026-03-31
Refused

Single story rear extension; alterations to side fenestrations; external alterations to flat

W32026-03-25
Granted

Details of plant, machinery and mechanical installations external noise level and mitigation measures pursuant to condition 7 of planning…

W52026-03-25
Granted

Details of external noise assessment and sound insulation of building envelope pursuant to condition 6 of planning permission ref: 251512…

W52026-03-25
Granted

Two storey side extension (following demolition of existing side extension); first floor side/rear extension

UB62026-03-25

These are borough-wide. See the 5 nearest to your address.

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Permitted Development Rules

Class APart 1

Enlargement, improvement or other alteration of a dwellinghouse

GPDO 2015, Schedule 2, Part 1, Class A

Rear extensions fall under Part 1, Class A of the General Permitted Development Order (GPDO). This means you can often build one without a full planning application, provided your project stays within the dimension limits.

Key dimension limits

Single storey

Up to 4m depthMax 4m heightMax 3m eaves height

Two storey

Up to 3m depthMust not exceed existing ridge heightMin 7m to rear boundary

These are the maximum GPDO limits for a detached house with no constraints. Your actual limits depend on your property type, location, and any planning restrictions.

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Typical Costs in London

Construction costs for rear extensions in London vary depending on size, specification, and whether you're building single or double storey.

Single storey rear extensionLondon

Cost per m²

£2,000£3,500

construction rate

Typical total

£25,000£50,000

Based on 12–18

Double storey rear extensionLondon

Cost per m²

£1,800£3,200

construction rate

Typical total

£40,000£80,000

Based on 20–35

Typically includes

FoundationsStructureRoofElectricsPlumbingBasic finishes

Typically excludes

Kitchen fittingPlanning application feeBuilding regs feeParty wall surveyorArchitect fees

Double storey extensions have a lower per-m² cost as foundations and roof are shared across two floors.

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Which Professionals Do You Need?

The professionals you'll need depend on the size and complexity of your extension, your property type, and whether you share walls with neighbours.

You'll need a party wall surveyor for this project.

Architect / designerOptional

A draughtsperson or architectural technician can prepare the plans needed for a single storey extension. A full architect may not be necessary.

Typical fee: £1,500£3,500 (Plans + Building Regs)

Structural engineerRecommended

Single storey extensions typically need structural calculations for any openings in existing walls and for foundations.

Typical fee: £500£1,500

Party wall surveyorEssential

Your semi-detached house shares a boundary with neighbours. Extensions and loft work within 3 metres of a shared wall trigger the Party Wall Act.

Typical fee: £700£1,500 (per neighbour)

Planning consultantNot needed

This guidance is based on a typical semi-detached house with no special constraints. Listed buildings, conservation areas, and attached properties may require additional professional input.

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Conservation Areas & Listed Buildings

If your property is in a conservation area, the maximum depth for a single storey rear extension is reduced to 3 metres for all property types. Two storey rear extensions are not permitted in conservation areas.

Conservation areas

Properties in conservation areas often have reduced permitted development rights. Some project types (like side extensions) lose PD rights entirely. An Article 4 Direction can remove additional PD rights.

Listed buildings

Listed buildings (Grade I, II*, or II) have no permitted development rights at all. Any external alteration requires Listed Building Consent in addition to any planning permission. An architect experienced in heritage work is essential.

Check if your property is in a conservation area or has other planning constraints.

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Prior Approval (Larger Home Extension Scheme)

What is Prior Approval?

Single storey rear extensions between 4m and 8m deep (detached) or 3m and 6m deep (other houses) may be built under the "larger home extension" scheme. This requires a Prior Approval application with a neighbour consultation — not a full planning application. The fee is lower and the decision is faster.

Frequently Asked Questions

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