House extension cost
in Raynes Park.
Raynes Park — SW20 — west of Wimbledon. Edwardian and inter-war housing dominates, with strong family-buyer demand from the Wimbledon and Kingston catchment.
What makes extension work in Raynes Park distinct.
Housing: Edwardian terraces and 1920s/30s semis, with some 1950s housing on the southern fringes.
Planning: Kingston Road and Cottenham Park conservation areas cover specific pockets; most of SW20 retains PD rights.
Applications go to LB Merton. We submit on your behalf and handle party wall awards, build-over agreements and conservation officer correspondence end-to-end.
The five extension types — SW20 numbers.
All figures inclusive of design, planning, build, contingency and VAT. The Raynes Park multiplier (0.90×) 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 Raynes Park and beyond.
Send me the guide.
What Raynes Park homeowners ask us.
How much does a house extension cost in Raynes Park in 2026?
Typical 2026 Raynes Park ranges (inc. design, planning, build, contingency & VAT): side-return extensions £81k–£144k; single-storey rear £99k–£189k; wraparound £153k–£288k; double-storey rear £162k–£342k; basement £225k–£675k. The Raynes Park multiplier (0.90×) reflects local labour rates, scaffold logistics and finish expectations.
Do I need planning permission for an extension in Raynes Park?
Kingston Road and Cottenham Park conservation areas cover specific pockets; most of SW20 retains PD rights. 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 Merton.
What extension type works best for Raynes Park houses?
Edwardian terraces and 1920s/30s semis, with some 1950s housing on the southern fringes. 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 Raynes Park?
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 Merton processes planning applications in approximately 8–13 weeks depending on backlog.
What hidden costs catch Raynes Park homeowners out on extensions?
In SW20 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 Raynes Park extensions?
Yes — Raynes Park is within our core London catchment. Our studio is at 20 Dawes Road in Fulham, 8.5km from Raynes Park. We've delivered extensions across the SW20 postcode and our subcontractor network covers Merton. Free site visit, fixed-price quote, 10-year HomePro guarantee on the finished work.
Extension pricing for Raynes Park’s neighbours.
Twenty minutes on site in Raynes Park.
On us.
Nick Elias RIBA and Vladimir will visit your Raynes Park 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 Raynes Park extension using the same 2026 rate card we quote real clients with.
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