House
extensions
in Clapham Junction, SW11
Architects, Engineers, Surveyors & Builders Under One Roof.
One Studio. One Contract. One Team.
RICS-regulated chartered surveying for party walls, licence to alter, conservation-area works & neighbour mattersWe design and build Clapham Junction house extensions across Clapham Junction's principal residential streets - side-return, rear, wraparound and double-storey additions for Victorian terraces, Between-The-Commons houses and Edwardian converted houses where planning strategy, conservation detailing, Party Wall sequencing and structural engineering need handling properly.
House Extensions in Clapham Junction: What You Need to Know
Every house extension project in Clapham Junction is designed to respect the Wandsworth Common West Side Conservation Area and the character of Victorian terraces, between-the-commons houses, Edwardian conversions. 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.
Clapham Junction 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 Clapham Junction 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.
Clapham Junction is defined by its 'between the commons' grid, and that coherence is exactly what the planning system guards. The area belongs to Wandsworth, with conservation areas including Wandsworth Common West Side, and the council examines external change and enforces Article 4 controls. Northcote Road is the lively spine, lined with shops; Battersea Rise, Webbs Road and the roads between Clapham and Wandsworth Commons carry long rows of bay-fronted Victorian terraces; and Lavender Hill adds mansion flats and conversions.
The stock makes the brief predictable but the detailing exacting. As classic family houses, they take a loft for an extra bedroom, a rear or side-return addition to open the kitchen to the garden, and whole-house refurbishment that renews services and reworks layout while keeping the bays and sash detail. On uniform terraces, an addition is set out to sit quietly in its run rather than break the rhythm of the street.
The build is a terrace exercise: party-wall awards, tight access and the rail-shaped street pattern all feed the budget. A Clapham Junction rear extension lands near £71,250 to £112,500 before VAT, a side return about £90,000 to £120,000.
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 Clapham Junction: Questions
How do Clapham Junction's conservation areas shape an extension?
Clapham Junction belongs to Wandsworth, and conservation areas including Wandsworth Common West Side protect the celebrated 'between the commons' grid. The council examines external change in its conservation areas and enforces Article 4 controls, so on those bay-fronted terraces an addition is measured against a tightly consistent streetscape.
Which Clapham Junction streets are the classic extension territory?
The grid off Northcote Road, between the commons. Northcote Road is the lively, shop-lined spine, while Battersea Rise, Webbs Road and the roads between Clapham and Wandsworth Commons carry long rows of bay-fronted Victorian family terraces; Lavender Hill adds mansion flats and conversions. These are classic family houses, so the work is lofts and rear or side-return additions.
What does a house extension cost in Clapham Junction?
London-wide guidance lands a Clapham Junction rear extension near £71,250 to £112,500 before VAT. A side return is a notch above, about £90,000 to £120,000, and a wraparound in an indicative £100,000 to £200,000 band. On the SW11 terraces the party-wall and access considerations move the figure as much as the added floor area.
What is the typical work on a Clapham Junction terrace?
These are classic family houses, so the brief tends to be a loft for an extra bedroom, a rear or side-return addition to open the kitchen to the garden, and whole-house refurbishment that renews services and reworks layout while keeping the bays and sash detail. Getting Wandsworth's conservation rules right early keeps a Clapham Junction project on track.
How does the railway history affect building around Clapham Junction?
It still shapes access. SW11 mixes Victorian terraces, mansion flats and the streets around Lavender Hill and St John's Hill, with the area's rail and transport past influencing how it grew and how sites are reached. On the between-the-commons grid, that context feeds into deliveries and logistics.
House Extensions in Nearby Areas
More Services in Clapham Junction
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We survey your property, discuss your vision and provide a clear budget framework.
Clapham Junction history & architecture
Background on the streets, buildings and conservation history of Clapham Junction: Lavender Hill History · Converting Lofts in Clapham Junction · Infrastructure and Clapham Junction Architecture · The Evolution of SW11 Terraces · The Early History of Clapham Junction · From Rural Lands to SW11 Suburbia