Rear extension in West Berkshire: Planning Permission Guide

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

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Rear extensions in West Berkshire at a glance

95%

approved

£548

application fee

8

weeks typical

Based on 146 decided applications in West Berkshire over 12 months (139 granted, 7 refused).

West Berkshire includes or borders the North Wessex Downs AONB — properties in or near those areas are on Article 1(5) land where permitted-development rights are restricted. West Berkshire has 51 conservation areas — extensive heritage coverage restricting external alterations across many streets. 9 Article 4 directions affect specific streets. 3,797 listed buildings recorded.

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

Recent rear extension decisions in West Berkshire

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

Granted

Erection of first floor rear extension above existing ground floor. Infill between garage block and house. Infill of recessed side porch.…

RG202026-05-21
Granted

Rear Extension and alterations

RG142026-05-20
Granted

Two storey rear extension

RG182026-05-15
Granted

Section 73 Application to vary conditions 2 (Approved Plans), 4 (Materials Schedule), 5 (Hard Landscaping), and 6 (External Doors and Win…

RG202026-05-13
Withdrawn

Demolition of existing rear extensions, replacement with a new single storey extension and adjacent car port with solar panels. Works to …

RG82026-05-11

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 South East England

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

Single storey rear extensionSouth East England

Cost per m²

£1,750£3,100

construction rate

Typical total

£23,000£45,000

Based on 12–18

Double storey rear extensionSouth East England

Cost per m²

£1,600£2,850

construction rate

Typical total

£35,000£70,000

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

Just want a quick yes/no for your rear extension?

Run our free 2-minute check to see whether your project likely qualifies as permitted development in West Berkshire. For personalised approval odds and nearby comparables, get the full report above.

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