House
extensions
in Wandsworth Town, SW18
Architects, Engineers, Surveyors & Builders Under One Roof.
One Studio. One Contract. One Team.
RICS surveying support for party walls, licence to alter, conservation-area works & neighbour mattersWe design and build Wandsworth Town house extensions across Wandsworth Town's principal residential streets - side-return, rear, wraparound and double-storey additions for Victorian terraces, Riverside Developments and Edwardian Semis where planning strategy, conservation detailing, Party Wall sequencing and structural engineering need handling properly.
House Extensions in Wandsworth Town: What You Need to Know
Every house extension project in Wandsworth Town is designed to respect the Wandsworth Town Conservation Area and the character of Victorian terraces, riverside developments, Edwardian semis. Our in-house RIBA Chartered Architects handle Wandsworth planning applications, our chartered structural engineers specify any load-bearing work, and our directly-employed trades deliver the build under one fixed-price contract. We coordinate Building Control, Party Wall awards where needed, and all certifications through to handover.
Wandsworth Town has conservation area coverage in parts, so some properties will need planning permission for external changes while others may proceed under permitted development. We assess each property individually.
Our house extension projects in Wandsworth Town are delivered by our in-house team of RIBA architects, structural engineers and specialist tradespeople. Every project is managed under a single fixed-price contract with no hidden costs.
The geography does the sorting in SW18. Wandsworth Town rises from the Thames towards the common, and the extension brief changes as the ground climbs: newer leasehold blocks gather by the river, Old York Road keeps its village heart beside the station, and East Hill and West Hill carry the substantial Victorian villas and terraces that make the area’s best extension candidates. A rear addition on the hills is a freehold conversation about gardens, drainage and party walls; an alteration in a riverside development answers first to the managing agent, with structure and acoustics agreed before design begins.
Most of our SW18 extension work lands on that hillside stock. The villas and terraces of East Hill and West Hill were built with the depth and rear space to absorb generous extensions and loft conversions, while the period houses around Old York Road ask for a quieter hand — they stand at the heart of the Wandsworth Town conservation area, which protects the best streets between the Thames and the common.
Pricing follows the ground as much as the design. Foundations and drainage behave differently on a slope, rear access varies house by house, trees and boundary conditions shape what can be built, and materials have to come through dense SW18 streets — all of it surveyed and costed before a contract is signed.
House Extensions in Wandsworth Town: Applied to the Local Stock
Wandsworth Town sits in the London Borough of Wandsworth, with the Wandsworth Town conservation area protecting its best streets between the Thames and the common. London-wide cost band for rear extension — single storey: £71,250–£112,500 excluding VAT (Resi rear extension cost guide, Oct 2025).
Sources: Wandsworth Council - Conservation area appraisals register (2026); Rear extension — single storey (Resi rear extension cost guide, Oct 2025) (2026)
What a House Extension Involves
An extension reshapes how the whole ground floor works, not just how big it is — the new structure, the opening into the existing house, the kitchen and the garden connection all have to be designed as one move. We take each project from feasibility drawings through consents, structure and fit-out under a single fixed-price contract. Most extensions we build include the scope below.
- Rear extensions — single-storey additions that open the back of the house to the garden
- Side-return & wraparound — infilling the side alley of a terrace, alone or combined with a rear addition
- Double-storey — new bedrooms or bathrooms above the ground-floor addition, designed to sit comfortably with the original roofline
- Foundations & steel — groundworks, beams and the opening into the existing house, engineered by our own structural team
- Glazing — rooflights, glazed roofs and slim-framed sliding or bi-fold doors specified for light and thermal performance
- Kitchen integration — the kitchen layout planned with the architecture from the first drawing, not squeezed in afterwards
- Services & heating — electrics, plumbing, drainage and underfloor heating built into the new floor
- External works — patio, drainage connections and garden reinstatement completed within the contract
How We Run Your Project
Six stages, with the consents and engineering settled before the first spade goes in.
- Feasibility visit — we assess the site, the boundaries and your brief, and identify the right consent route for your property.
- Design & approvals — our architects draw the scheme while planning or permitted development paperwork, structural calculations and party wall notices progress together.
- Fixed-price contract — every element specified and priced before construction, from foundations to door hardware.
- Groundworks & shell — excavation, foundations, walls, steel and roof, taken to weathertight while you carry on living in the house.
- Fit-out — insulation, services, glazing, kitchen, flooring and decoration, with the opening into the existing house formed once the shell is sealed.
- Completion — building control inspection, snagging, external works and handover with the full certification pack.
Read the full house extension guide for extension types, permitted development limits and the build programme stage by stage.
Many rear extensions can proceed under permitted development — broadly up to 3m deep on attached houses and 4m on detached, extendable to 6m and 8m through the prior approval scheme — but conservation areas, Article 4 directions and listed status change the picture, and every extension needs Building Regulations approval regardless of the planning route. Where foundations come within 3m of a neighbouring building, the Party Wall etc. Act 1996 obliges you to give adjoining owners a minimum of two months’ written notice before construction can begin. Our planning guide library sets out the rules for each borough.
Why Hampstead Renovations
We hold £10 million public liability insurance with Aviva; the certificate is available on request.
House Extensions in Wandsworth Town: Questions
Is Wandsworth Town covered by a conservation area?
Yes — the Wandsworth Town conservation area protects the area's best streets between the Thames and the common. Because early knowledge of the council's conservation rules is what keeps a scheme here on track, every Wandsworth Town extension enquiry with us begins with a status check on your street.
What extension work is typical in Wandsworth Town?
A wide range. SW18 combines Victorian terrace housing, family streets, mews pockets and newer riverside development, so extension work runs from straightforward rear additions to older houses through to careful structural interfaces near mixed urban sites. The substantial Victorian villas of East Hill and West Hill take lofts and rear extensions particularly well.
What should I plan for structurally when extending in Wandsworth Town?
Party-wall agreements with the neighbouring terrace come first; then foundations and drainage, access to the rear, trees and boundary conditions, the structural openings back into the existing house, and sourcing external materials that match — all sequenced around the practicalities of working in dense SW18 streets. We survey and price each element before the contract is signed, not after.
Can I extend in Wandsworth Town under permitted development?
Never assume so. Wandsworth applies Article 4 controls and looks hard at external change within its conservation areas, which means extension elements that would pass as permitted development elsewhere can require a full application on a protected SW18 street. Establishing Wandsworth’s conservation position at the outset is what keeps a scheme here on programme.
What does a rear extension cost in Wandsworth Town?
Budget from the London-wide band of £71,250–£112,500 excluding VAT for a single-storey rear extension; a side-return extension typically runs £90,000–£120,000 excluding VAT. On the Victorian villas of East Hill and West Hill, where a project lands depends on how the slope treats foundations, drainage and access to the rear.
Local character & heritage: extending in Wandsworth Town
Wandsworth Town sits in the London Borough of Wandsworth, and extending here means working with Victorian terraced family houses, including the Tonsleys. Where houses and gardens allow, side-return and rear extensions open up the living space; in the many flats, the equivalent is internal reconfiguration and, where possible, lower-ground additions.
Permitted-development rights are usually restricted in Wandsworth Town's conservation areas, so most extensions need a full householder application, and the conservation-area terraces are consistent and protected. We design every extension to respect the period frontage and to win consent.
Wandsworth Town heritage & architecture: Roof developments & conservation · Conservation areas · Listed buildings · Renovating a period terrace · Period facades · Facade planning rules
House Extensions in Wandsworth Town: Planning & Local Context
London Borough of Wandsworth · SW18
Planning for house extensions in Wandsworth Town
Rear and side-return extensions are popular in Wandsworth Town, but permitted-development rights are frequently restricted within Wandsworth Town's conservation areas, so most extensions need a full planning application to London Borough of Wandsworth with design that respects the prevailing building line and materials.
London Borough of Wandsworth context
Wandsworth Town SW18 sits within Wandsworth Town's conservation areas, and Wandsworth's Local Plan and conservation-area controls shape rear, side-return and roof alterations across its Victorian terraces. Our in-house RIBA Chartered Architects prepare and submit every application to London Borough of Wandsworth and handle pre-application discussions where early planning advice is useful.
Building Regulations
House Extensions in Wandsworth Town must satisfy Building Regulations — covering structural design to Part A, thermal performance to Part L, and drainage and foundations agreed with Building Control. Our in-house engineers manage Building Control from initial notice to completion certificate.
Recent work & local links
Explore our other Wandsworth Town services — Kitchen Renovation Loft Conversions — or the Wandsworth Town renovation hub.
Our in-house planning team prepares and submits every London Borough of Wandsworth application and manages building control end to end. View our planning track record →
House Extensions in Nearby Areas
More Services in Wandsworth Town
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We survey your property, discuss your vision and provide a clear budget framework.