House extension cost
in West Kensington.
West Kensington — the W14 streets north of Talgarth Road. Mansion blocks dominate the main roads; behind them is a grid of late-Victorian and Edwardian terraces with strong loft potential.
What makes extension work in West Kensington distinct.
Housing: Late-Victorian terraces with tile-hung gables and outriggers, plus large red-brick mansion blocks on the main roads.
Planning: Parts of W14 fall within Edith Road Conservation Area and Olympia Conservation Area — these need full planning, while the eastern blocks toward Earls Court Road often retain PD rights.
Applications go to LB Hammersmith & Fulham. We submit on your behalf and handle party wall awards, build-over agreements and conservation officer correspondence end-to-end.
The five extension types — W14 numbers.
All figures inclusive of design, planning, build, contingency and VAT. The West Kensington multiplier (1.08×) reflects local labour, scaffolding logistics, conservation requirements and finish expectations.
The 2026 London Extension Cost Guide.
Borough-by-borough pricing, a full £200k cost breakdown, PD vs full planning explained, and the seven hidden costs to watch for in West Kensington and beyond.
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What West Kensington homeowners ask us.
How much does a house extension cost in West Kensington in 2026?
Typical 2026 West Kensington ranges (inc. design, planning, build, contingency & VAT): side-return extensions £97k–£173k; single-storey rear £119k–£227k; wraparound £184k–£346k; double-storey rear £194k–£410k; basement £270k–£810k. The West Kensington multiplier (1.08×) reflects local labour rates, scaffold logistics and finish expectations.
Do I need planning permission for an extension in West Kensington?
Parts of W14 fall within Edith Road Conservation Area and Olympia Conservation Area — these need full planning, while the eastern blocks toward Earls Court Road often retain PD rights. Outside conservation areas, single-storey rear extensions up to 3m (terrace/semi) or 4m (detached) usually qualify for permitted development. Side-returns, wraparounds, double-storey extensions and anything in a conservation area need full planning. Applications go to LB Hammersmith & Fulham.
What extension type works best for West Kensington houses?
Late-Victorian terraces with tile-hung gables and outriggers, plus large red-brick mansion blocks on the main roads. On this housing stock, the most common 2VP extension is a single-storey rear or wraparound — adding 20–35 m² of open-plan kitchen-diner. Double-storey extensions become viable on properties with rear gardens deep enough to absorb the additional volume without overshadowing.
How long does an extension take in West Kensington?
Allow 8–12 weeks for design and planning (longer in conservation areas), then 16–22 weeks on site for a single-storey, 22–30 weeks for a wraparound or double-storey, and 28–40 weeks for a basement. LB Hammersmith & Fulham processes planning applications in approximately 8–13 weeks depending on backlog.
What hidden costs catch West Kensington homeowners out on extensions?
In W14 the top items are: party wall awards (£1,000–£3,000 per neighbour — common on terraced streets), build-over agreements with Thames Water (£300–£1,500 where drains run beneath the proposed extension), conservation officer consultations, structural engineer fees, drainage and asbestos surveys, and VAT at 20% on top of the base build cost. All of these are itemised in our fixed-price quote.
Does 2VP work on West Kensington extensions?
Yes — West Kensington is within our core London catchment. Our studio is at 20 Dawes Road in Fulham, 1.6km from West Kensington. We've delivered extensions across the W14 postcode and our subcontractor network covers Hammersmith & Fulham. Free site visit, fixed-price quote, 10-year HomePro guarantee on the finished work.
Extension pricing for West Kensington’s neighbours.
Twenty minutes on site in West Kensington.
On us.
Nick Elias RIBA and Vladimir will visit your West Kensington home, walk the site, check planning constraints, advise on PD vs full planning, and give you a realistic budget and programme — even if an extension isn’t the right move.
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Price your West Kensington extension using the same 2026 rate card we quote real clients with.
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