House extension cost
in Dulwich.
Dulwich — SE21 — one of inner-south London's most prestigious postcodes, anchored by the Dulwich Picture Gallery and the village green. Generous Edwardian and Victorian housing with consistently strong property values.
What makes extension work in Dulwich distinct.
Housing: Victorian and Edwardian villas, Edwardian terraces, and some inter-war housing on the eastern slopes.
Planning: Dulwich Village, College Road and Dulwich Wood conservation areas cover most of the central streets. The Dulwich Estate has its own design covenants.
Applications go to LB Southwark. We submit on your behalf and handle party wall awards, build-over agreements and conservation officer correspondence end-to-end.
The five extension types — SE21 numbers.
All figures inclusive of design, planning, build, contingency and VAT. The Dulwich multiplier (1.02×) 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 Dulwich and beyond.
Send me the guide.
What Dulwich homeowners ask us.
How much does a house extension cost in Dulwich in 2026?
Typical 2026 Dulwich ranges (inc. design, planning, build, contingency & VAT): side-return extensions £92k–£163k; single-storey rear £112k–£214k; wraparound £173k–£326k; double-storey rear £184k–£388k; basement £255k–£765k. The Dulwich multiplier (1.02×) reflects local labour rates, scaffold logistics and finish expectations.
Do I need planning permission for an extension in Dulwich?
Dulwich Village, College Road and Dulwich Wood conservation areas cover most of the central streets. The Dulwich Estate has its own design covenants. 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 Southwark.
What extension type works best for Dulwich houses?
Victorian and Edwardian villas, Edwardian terraces, and some inter-war housing on the eastern 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 Dulwich?
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 Southwark processes planning applications in approximately 8–13 weeks depending on backlog.
What hidden costs catch Dulwich homeowners out on extensions?
In SE21 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 Dulwich extensions?
Yes — Dulwich is within our core London catchment. Our studio is at 20 Dawes Road in Fulham, 9.0km from Dulwich. We've delivered extensions across the SE21 postcode and our subcontractor network covers Southwark. Free site visit, fixed-price quote, 10-year HomePro guarantee on the finished work.
Extension pricing for Dulwich’s neighbours.
Twenty minutes on site in Dulwich.
On us.
Nick Elias RIBA and Vladimir will visit your Dulwich 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 Dulwich extension using the same 2026 rate card we quote real clients with.
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