House extension cost
in Hampstead.
Hampstead — NW3 — north of Camden on the heath. Georgian and Victorian houses, with one of London's most architecturally protected residential neighbourhoods.
What makes extension work in Hampstead distinct.
Housing: Georgian and Victorian houses, plus Edwardian terraces and Arts & Crafts villas on the western slopes.
Planning: Hampstead Conservation Area covers virtually the entire neighbourhood. Many properties are listed.
Applications go to LB Camden. We submit on your behalf and handle party wall awards, build-over agreements and conservation officer correspondence end-to-end.
The five extension types — NW3 numbers.
All figures inclusive of design, planning, build, contingency and VAT. The Hampstead 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 Hampstead and beyond.
Send me the guide.
What Hampstead homeowners ask us.
How much does a house extension cost in Hampstead in 2026?
Typical 2026 Hampstead 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 Hampstead multiplier (1.20×) reflects local labour rates, scaffold logistics and finish expectations.
Do I need planning permission for an extension in Hampstead?
Hampstead Conservation Area covers virtually the entire neighbourhood. 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 LB Camden.
What extension type works best for Hampstead houses?
Georgian and Victorian houses, plus Edwardian terraces and Arts & Crafts villas on the western slopes. 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 Hampstead?
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 Camden processes planning applications in approximately 8–13 weeks depending on backlog.
What hidden costs catch Hampstead homeowners out on extensions?
In NW3 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 Hampstead extensions?
Yes — Hampstead is within our core London catchment. Our studio is at 20 Dawes Road in Fulham, 8.5km from Hampstead. We've delivered extensions across the NW3 postcode and our subcontractor network covers Camden. Free site visit, fixed-price quote, 10-year HomePro guarantee on the finished work.
Extension pricing for Hampstead’s neighbours.
Twenty minutes on site in Hampstead.
On us.
Nick Elias RIBA and Vladimir will visit your Hampstead 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 Hampstead extension using the same 2026 rate card we quote real clients with.
Price my Hampstead extension →