House extension cost
in Richmond.
Richmond — TW9/TW10 — one of London's most prestigious outer postcodes, with Richmond Park, the Thames and a genuine historic town centre. Property values rival inner-west London on prime streets.
What makes extension work in Richmond distinct.
Housing: Georgian and Victorian houses on Richmond Hill and around the green, Edwardian terraces and semis on the slopes below.
Planning: Richmond Hill, Richmond Green and Richmond Town conservation areas cover most of central Richmond. Many properties are listed.
Applications go to LB Richmond upon Thames. We submit on your behalf and handle party wall awards, build-over agreements and conservation officer correspondence end-to-end.
The five extension types — TW9 numbers.
All figures inclusive of design, planning, build, contingency and VAT. The Richmond multiplier (1.12×) 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 Richmond and beyond.
Send me the guide.
What Richmond homeowners ask us.
How much does a house extension cost in Richmond in 2026?
Typical 2026 Richmond ranges (inc. design, planning, build, contingency & VAT): side-return extensions £101k–£179k; single-storey rear £123k–£235k; wraparound £190k–£358k; double-storey rear £202k–£426k; basement £280k–£840k. The Richmond multiplier (1.12×) reflects local labour rates, scaffold logistics and finish expectations.
Do I need planning permission for an extension in Richmond?
Richmond Hill, Richmond Green and Richmond Town conservation areas cover most of central Richmond. 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 Richmond upon Thames.
What extension type works best for Richmond houses?
Georgian and Victorian houses on Richmond Hill and around the green, Edwardian terraces and semis on the slopes below. 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 Richmond?
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 Richmond upon Thames processes planning applications in approximately 8–13 weeks depending on backlog.
What hidden costs catch Richmond homeowners out on extensions?
In TW9 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 Richmond extensions?
Yes — Richmond is within our core London catchment. Our studio is at 20 Dawes Road in Fulham, 8.0km from Richmond. We've delivered extensions across the TW9 postcode and our subcontractor network covers Richmond upon Thames. Free site visit, fixed-price quote, 10-year HomePro guarantee on the finished work.
Extension pricing for Richmond’s neighbours.
Twenty minutes on site in Richmond.
On us.
Nick Elias RIBA and Vladimir will visit your Richmond 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 Richmond extension using the same 2026 rate card we quote real clients with.
Price my Richmond extension →