Extending a Chelsea house calls for careful design on small, tightly packed plots. TrustBuilt Projects builds rear, side-return and structurally glazed garden extensions across SW3 and SW10 — from the artisan cottages around World's End to the Georgian terraces off the King's Road and the riverside streets near Cheyne Walk — all managed by us within the Royal Borough's conservation control.
Chelsea's housing runs from grand Georgian terraces off the King's Road and around Carlyle Square to the smaller, narrower artisan cottages towards World's End in SW10, and the riverside houses near Cheyne Walk and the Embankment. On these tighter plots a rear or side-return extension, often glazed onto a small courtyard garden, is usually the way to win light and living space without touching the protected frontage.
Almost all of SW3 and SW10 lies within the Royal Borough's conservation areas — Cheyne, Chelsea Park and the others — so extensions here are generally a full planning matter rather than permitted development, and listed houses need listed building consent. On the riverside streets close to the Thames, ground conditions and flood-risk also feed into the design, which is why we survey carefully before committing to anything below ground.
The narrow streets off the King's Road and around World's End make access for materials and muck-away a genuine constraint, and the cottages and terraces here share boundaries on both sides, so Party Wall awards are nearly always required. We handle the notices, coordinate the architect and structural engineer, and build to the specification a prime Chelsea house demands.
Chelsea extension costs reflect the tight terraced plots, the glazing quality owners want onto courtyard gardens, and the conservation detailing the Royal Borough requires. Typical ranges:
| Project type | Typical cost | Timeline |
|---|---|---|
| Side-return extension | £68,000 – £115,000 | 14–22 weeks |
| Rear extension (single-storey) | £72,000 – £125,000 | 14–22 weeks |
| Structural-glazed / garden extension | £95,000 – £175,000 | 18–28 weeks |
| Lower-ground / vault extension | from £135,000 | 20–32 weeks |
Every project is quoted in writing after a free site visit — these ranges are a guide only.
In nearly all cases yes. Almost all of SW3 and SW10 sits within a conservation area, so permitted development rights are usually restricted and most rear or side-return extensions need full planning permission — and a listed house also needs listed building consent. We confirm your address's status before pricing.
It can, especially for anything below ground. The streets near the Thames sit where groundwater is higher and flood-risk has to be considered, so we carry out the right ground survey and factor drainage and waterproofing into the design before we price a lower-ground scheme.
On the smaller SW10 cottages a modest rear or side-return extension, glazed for daylight onto the courtyard, usually adds the most without overwhelming the house. On the larger Georgian terraces around Carlyle Square there's scope for a fuller rear or lower-ground addition. We design to what your specific plot will take.
Almost always — Chelsea's terraces and cottages are built right up to the boundary you share on both sides, so the Party Wall Act applies once you build up to or near the line. We serve the notices and coordinate surveyors, and plan access around the narrow streets, as part of running the project.
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