The side-return kitchen extension is the signature Clapham project — and the one we build most. TrustBuilt Projects designs and builds side-return, rear and wrap-around extensions across Clapham Old Town, North, South and Common (SW4, SW8, SW11), all managed by us.
Clapham's Victorian terraces almost all have the same quirk: a narrow rear 'back addition' with a useless side alley beside it. The side-return extension fills that alley and opens the ground floor into a wide kitchen-diner — it's the single most transformative thing you can do to one of these houses, and it's our most-requested Clapham job.
Many side-return and rear extensions fall under permitted development, but the Clapham Old Town conservation area tightens the rules, and a wrap-around (side-return plus rear) usually needs full planning. We confirm the route for your specific address before anything is priced.
Party Wall agreements are almost always needed because you're building right up to the boundary with neighbours, and access on terraced streets is tight. We handle the notices, sequence deliveries carefully, and keep the house liveable for as much of the build as possible.
Clapham extension costs are driven by size, glazing and kitchen spec, plus the tight-access premium common on terraced streets. Typical ranges:
| Project type | Typical cost | Timeline |
|---|---|---|
| Side-return extension | £55,000 – £85,000 | 12–18 weeks |
| Rear extension (single-storey) | £50,000 – £80,000 | 12–16 weeks |
| Wrap-around extension | £80,000 – £130,000 | 16–24 weeks |
| Double-storey extension | £95,000 – £160,000 | 20–28 weeks |
Every project is quoted in writing after a free site visit — these ranges are a guide only.
It fills the narrow alley beside the rear back addition of a Victorian terrace, widening the ground floor into an open-plan kitchen-diner. Because almost every Clapham terrace has that wasted side-return, it's the highest-impact extension you can do here — which is why it's our most common SW4 project.
Many single-storey side-return and rear extensions fall under permitted development, but the Clapham Old Town conservation area tightens the rules and wrap-around or double-storey extensions usually need full planning. We confirm at the free site visit.
Almost certainly — extensions build up to the boundary you share with neighbours, so the Party Wall Act applies. We serve the notices and can recommend trusted local surveyors.
Usually yes, though the kitchen is out of action for part of the build. We talk through a temporary kitchen setup and sequence the works to minimise disruption.
Free site visit, no obligation, written quote.
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