House extension cost
in St John's Wood.
St John's Wood — NW8 — north of Marylebone, with leafy streets of Italianate villas and Edwardian mansion blocks. One of London's most settled residential neighbourhoods.
What makes extension work in St John's Wood distinct.
Housing: Italianate stucco villas, red-brick Edwardian mansion blocks, and detached houses on the prime streets near Lord's.
Planning: St John's Wood Conservation Area covers most of NW8. Article 4 directions remove PD rights on key streets.
Applications go to City of Westminster. We submit on your behalf and handle party wall awards, build-over agreements and conservation officer correspondence end-to-end.
The five extension types — NW8 numbers.
All figures inclusive of design, planning, build, contingency and VAT. The St John's Wood multiplier (1.20×) 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 St John's Wood and beyond.
Send me the guide.
What St John's Wood homeowners ask us.
How much does a house extension cost in St John's Wood in 2026?
Typical 2026 St John's Wood ranges (inc. design, planning, build, contingency & VAT): side-return extensions £108k–£192k; single-storey rear £132k–£252k; wraparound £204k–£384k; double-storey rear £216k–£456k; basement £300k–£900k. The St John's Wood multiplier (1.20×) reflects local labour rates, scaffold logistics and finish expectations.
Do I need planning permission for an extension in St John's Wood?
St John's Wood Conservation Area covers most of NW8. Article 4 directions remove PD rights on key streets. 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 City of Westminster.
What extension type works best for St John's Wood houses?
Italianate stucco villas, red-brick Edwardian mansion blocks, and detached houses on the prime streets near Lord's. 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 St John's Wood?
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. City of Westminster processes planning applications in approximately 8–13 weeks depending on backlog.
What hidden costs catch St John's Wood homeowners out on extensions?
In NW8 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 St John's Wood extensions?
Yes — St John's Wood is within our core London catchment. Our studio is at 20 Dawes Road in Fulham, 7.0km from St John's Wood. We've delivered extensions across the NW8 postcode and our subcontractor network covers Westminster. Free site visit, fixed-price quote, 10-year HomePro guarantee on the finished work.
Extension pricing for St John's Wood’s neighbours.
Twenty minutes on site in St John's Wood.
On us.
Nick Elias RIBA and Vladimir will visit your St John's Wood 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.
One number. Sixty seconds. No callback.
Price your St John's Wood extension using the same 2026 rate card we quote real clients with.
Price my St John's Wood extension →