House extension cost
in Kensington.
Kensington — W8 — runs from Notting Hill to South Kensington. Some of the most expensive postcodes in London, with housing ranging from Georgian terraces around Kensington Square to Italianate Victorian villas.
What makes extension work in Kensington distinct.
Housing: Georgian and early Victorian terraces, large stucco villas, plus garden-square set-pieces like Kensington Square and Edwardes Square.
Planning: The entire W8 postcode falls within Kensington Conservation Area, with overlapping Edwardes Square, De Vere and Phillimore conservation areas. Many properties are listed.
Applications go to Royal Borough of Kensington & Chelsea. We submit on your behalf and handle party wall awards, build-over agreements and conservation officer correspondence end-to-end.
The five extension types — W8 numbers.
All figures inclusive of design, planning, build, contingency and VAT. The Kensington multiplier (1.25×) 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 Kensington and beyond.
Send me the guide.
What Kensington homeowners ask us.
How much does a house extension cost in Kensington in 2026?
Typical 2026 Kensington ranges (inc. design, planning, build, contingency & VAT): side-return extensions £113k–£200k; single-storey rear £138k–£263k; wraparound £213k–£400k; double-storey rear £225k–£475k; basement £313k–£938k. The Kensington multiplier (1.25×) reflects local labour rates, scaffold logistics and finish expectations.
Do I need planning permission for an extension in Kensington?
The entire W8 postcode falls within Kensington Conservation Area, with overlapping Edwardes Square, De Vere and Phillimore conservation areas. Many properties are listed. 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 Royal Borough of Kensington & Chelsea.
What extension type works best for Kensington houses?
Georgian and early Victorian terraces, large stucco villas, plus garden-square set-pieces like Kensington Square and Edwardes Square. 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 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. Royal Borough of Kensington & Chelsea processes planning applications in approximately 8–13 weeks depending on backlog.
What hidden costs catch Kensington homeowners out on extensions?
In W8 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 Kensington extensions?
Yes — Kensington is within our core London catchment. Our studio is at 20 Dawes Road in Fulham, 2.5km from Kensington. We've delivered extensions across the W8 postcode and our subcontractor network covers Kensington & Chelsea. 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.
Extension pricing for Kensington’s neighbours.
Twenty minutes on site in Kensington.
On us.
Nick Elias RIBA and Vladimir will visit your 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.
A real studio, a short drive from 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.
One number. Sixty seconds. No callback.
Price your Kensington extension using the same 2026 rate card we quote real clients with.
Price my Kensington extension →The home you actually want, finished on the date in the contract — and you watch every day of it happen from your phone.
- Your number in 60 seconds
- Itemised stage breakdown in 2 minutes
- Survey within 7 days
You answer 3 questions. We do the drawings, planning, party wall, trades and snagging.
- 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.
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.
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.
Extension went smoothly from start to finish. Communication was great throughout, and the team delivered exactly what we asked for. Thank you, 2VP!
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.
- 12-month workmanship warranty on second-fix fittings
- £5M public liability
- £10M employer's liability
- £2M professional indemnity
- HomePro insurance-backed guarantee, 10 years
- Priced at 2.5% of the contract sum
- Underwritten by an insurer, so it survives 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