Extension cost London/West Kensington
W14 · Hammersmith & Fulham · 2026 prices

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.

£119k–£227k
West Kensington single-storey rear extension, all-in
W14
Hammersmith & Fulham
1.6 km
from our Fulham studio
12-month
Workmanship warranty on second-fix fittings, signed by the trades
West Kensington housing stock & planning

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.

Streets we work in West Kensington
Edith RoadSinclair RoadAvonmore RoadGunterstone RoadCharleville Road
Extension prices for West Kensington, by type

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.

Side-return extension
West Kensington typical
£97k – £173k
The classic SW London infill — captures the dead alley alongside the kitchen. Usually PD-compliant outside conservation areas.
Single-storey rear
West Kensington typical
£119k – £227k
Full-width rear pop-out. The most common kitchen-diner upgrade.
Wraparound (side + rear)
West Kensington typical
£184k – £346k
Side-return + rear combined. Transformative for Victorian terraces. Usually full planning.
Double-storey rear
West Kensington typical
£194k – £410k
Adds bedroom + bathroom upstairs over the kitchen extension. Best value per m².
Basement / cellar dig-out
West Kensington typical
£270k – £810k
Highest cost, highest disruption, highest value. Always needs party wall awards.
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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.

Five sections — London ranges, borough multipliers, where the money goes, the costs that catch people out, and how to read a builder's quote.
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West Kensington extension FAQ

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 itemised quotation.

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, itemised quotation, 12-month workmanship warranty on second-fix fittings on the finished work — with an optional 10-year HomePro guarantee on request, arranged with HomePro and paid directly to them at 2.5% of the contract value.

Nicholas Elias RIBA
Vladimir Castravet
Free site visit · West Kensington

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.

Ready to build in West Kensington?
See our extension work in West Kensington.
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Who you are dealing with

A real studio, a short drive from West Kensington.

One company, one address, one registered number — not a lead form that sells your details on. You can walk into the office on Dawes Road and ask for Vladimir by name.

Company2V Projects Ltd (2VP)
Address20 Dawes Road, London SW6 7EN
Phone020 8050 8968
Emailhi@2vp.uk
HoursMonday to Friday, 8am to 6pm
Registered in England & WalesNo. 14122250
ServingWest Kensington W14

See the studio on Google Maps

The studio at 20 Dawes Road, London SW6 7EN. Surveys are booked from here and the project manager drives out from here.

One number. Sixty seconds. No callback.

Price your West Kensington extension using the same 2026 rate card we quote real clients with.

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If this is your project

The home you actually want, finished on the date in the contract — and you watch every day of it happen from your phone.

How fast
  • Your number in 60 seconds
  • Itemised stage breakdown in 2 minutes
  • Survey within 7 days
What you do

You answer 3 questions. We do the drawings, planning, party wall, trades and snagging.

What protects you
  • 10% to mobilise, then weekly against work already done — with 5% held past handover: 2.5% released at practical completion and 2.5% at the end of the 12-month defects period
  • £550 survey fee credited in full against your contract
  • Every variation priced and signed before a penny is spent

The date is a term of the contract. We finish on the agreed date, or we pay you £500 for every week we are late.

Do not take our word for it

4.8 from 16 Google reviews

Every review is published in full on our reviews page, including the one-star. Google is the only platform we quote a rating for, because it is the only one we can evidence.

★★★★★
As a structural engineer, I've collaborated with 2VP Projects Ltd on several residential projects in London. Their attention to detail, proactive site management, and clear communication make every stage—from design to execution—smooth and efficient. It's rare to find a contractor who values both precision and professionalism at this level. A truly reliable partner.
Igors Smirnovs · Structural engineer we have worked with · June 2025
★★★★★
Great company to work with. Professional, reliable and easy to deal with. Vladimir and the team are always responsive, straightforward and genuinely care about doing things properly. I've had a very positive experience working with 2VP and would happily recommend them.
Sheen Delicatessen · Business client · August 2026
★★★★★
Extension went smoothly from start to finish. Communication was great throughout, and the team delivered exactly what we asked for. Thank you, 2VP!
Dan Martea · August 2026
Warranties and protections

What is covered, and by whom

A builder’s own guarantee is worth exactly as much as the company standing behind it. Here is what comes as standard, what you can add, and what has to come from somebody other than us — set out in full on our insurance and guarantee page.

Included in the contract
  • 12-month workmanship warranty on second-fix fittings
  • £5M public liability
  • £10M employer's liability
  • £2M professional indemnity
Optional, on request
  • HomePro insurance-backed guarantee, 10 years
  • Priced at 2.5% of the contract sum
  • Underwritten by an insurer, so it survives us
Not from us
  • 10-year structural warranty on a new dwelling (NHBC / LABC / Premier)
  • Professional fees — architect, engineer, building control
  • We will tell you when you need one rather than let you find out