Wraparound extension in Merton: Planning Permission Guide

Your guide to wraparound extensions in Merton — combining rear and side extensions under one project.

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Wraparound extensions in Merton at a glance

95%

approved *

£258

application fee

8

weeks typical

Based on 19 decided applications in Merton over 12 months (18 granted, 1 refused). * Limited data — treat as indicative.

Merton has conservation areas including Wimbledon Village, Wimbledon Common, Mitcham Cricket Green, and Cannizaro Park. Listed buildings cluster around Wimbledon Common and Merton Abbey Mills. Wimbledon Common is Metropolitan Common Land with its own byelaws near the edges. Article 4 Directions cover parts of Wimbledon Village. The borough has a mix of affluent Edwardian housing around Wimbledon and Victorian terrace stock in Mitcham and Colliers Wood.

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

Recent wraparound extension decisions in Merton

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

No Further Action

TELECOMS REG 5 APPLICATION FOR EXISTING 11.7M HIGH MONOPOLE TO BE REMOVED AND REPLACED WITH A NEW 20M HIGH STREETWORKS POLE WITH WRAPAROU…

2026-04-05
Withdrawn

REAR AND SIDE OF PROPERTY: ROW OF CONIFERS AND 1 X CHERRY TREE LAURELREMOVAL OF ONE DYING YEW TREE; CUT BACK OVERHANGING BRANCHES FROM VA…

SW202026-03-23
Granted

APPLICATION FOR THE ERECTION OF A SINGLE-STOREY GROUND FLOOR WRAP-AROUND REAR AND SIDE INFILL EXTENSION, INCLUDING INTERNAL AND EXTERNAL …

SW192026-01-26
Granted

ERECTION OF A PART ONE, PART TWO STOREY REAR WRAP AROUND EXTENSION. ADDITION OF WINDOWS AND A ROOF LIGHT

SW192026-01-19
Granted

APPLICATION FOR THE ERECTION OF A SIDE AND REAR ROOF EXTENSION.

SW192026-01-19

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

A wraparound extension combines a rear and side extension. It's assessed under Part 1, Class A of the GPDO and must comply with the limits for both rear depth and side width.

Key dimension limits

Rear: up to 4m depthSide: max 2.8m widthMax 4m height, single storey

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

Wraparound extensions cost more than a simple rear or side extension due to the larger footprint and more complex structural requirements.

Single storey wraparound extensionLondon

Cost per m²

£2,000£3,500

construction rate

Typical total

£45,000£90,000

Based on 20–30

Typically includes

FoundationsStructureRoofElectricsPlumbingBasic finishes

Typically excludes

Kitchen fittingPlanning application feeBuilding regs feeParty wall surveyorArchitect fees

Combines rear and side extension. Costs at the higher end due to larger footprint and structural complexity.

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Which Professionals Do You Need?

Wraparound extensions have complex geometry with multiple roof junctions and typically benefit from professional design input.

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

Architect / designerRecommended

Wraparound extensions have complex geometry with multiple roof junctions that benefit from professional design.

Typical fee: £2,000£5,000 (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

In conservation areas, the side element of a wraparound extension is not permitted development. The rear element is limited to 3 metres depth.

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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Frequently Asked Questions

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

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

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