House extension cost
in South Kensington.
South Kensington — SW7 — the museum quarter and one of the densest concentrations of Italianate Victorian terraces in London. The Onslow, Brompton and Cromwell grid is among RBKC's most architecturally protected.
What makes extension work in South Kensington distinct.
Housing: Tall Italianate stucco terraces, four to five storeys, mostly converted to large flats with some intact single-family homes.
Planning: Thurloe-Smith's Charity, Brompton, Queen's Gate and Cornwall conservation areas overlap across SW7. Listed-building consent is common.
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 — SW7 numbers.
All figures inclusive of design, planning, build, contingency and VAT. The South 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 South Kensington and beyond.
Send me the guide.
What South Kensington homeowners ask us.
How much does a house extension cost in South Kensington in 2026?
Typical 2026 South 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 South Kensington multiplier (1.25×) reflects local labour rates, scaffold logistics and finish expectations.
Do I need planning permission for an extension in South Kensington?
Thurloe-Smith's Charity, Brompton, Queen's Gate and Cornwall conservation areas overlap across SW7. Listed-building consent is common. 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 South Kensington houses?
Tall Italianate stucco terraces, four to five storeys, mostly converted to large flats with some intact single-family homes. 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 South 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 South Kensington homeowners out on extensions?
In SW7 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 South Kensington extensions?
Yes — South Kensington is within our core London catchment. Our studio is at 20 Dawes Road in Fulham, 3.0km from South Kensington. We've delivered extensions across the SW7 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 South Kensington’s neighbours.
Twenty minutes on site in South Kensington.
On us.
Nick Elias RIBA and Vladimir will visit your South 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 South 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 South Kensington extension using the same 2026 rate card we quote real clients with.
Price my South 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