The whole spectrum — rear extensions, side returns, wraparounds, double-storey, basement digs. Planning-led design with detailed technical phase, ideal for Victorian terraces across Clapham, Hackney, Islington and beyond.
Measured existing survey, photographic record, Article 4 and conservation check before we quote design.
2–3 design options at concept stage — we explore alternative layouts, glazing and roof forms before committing.
Site location plan, existing and proposed plans, elevations, sections, Design & Access Statement where required.
Part L thermal, Part B fire, Part M accessibility, structural strategy coordinated with engineer.
Steel beam, foundation, lintel design. Chartered engineer. Submitted to Building Control.
Party Wall notices where needed; Thames Water Build Over Agreement where you're within 3m of a public sewer.
Every case is different. Call 020 7946 0000 for a five-minute chat.
Start a free quote →Single-storey rear extensions up to 3m (attached) or 4m (detached) fall under standard PD; up to 6m/8m under Prior Approval (Class AA). Side extensions up to half the width of the house. Not available on flats or in Article 4 areas.
Most outer boroughs allow single-storey basement. Camden, RBKC and Westminster have strict policies limiting basement depth and coverage. We advise on viability at the first site visit.
Usually to the full side-passage depth — typically 1.8–2.2m wide, running the full length of the original kitchen/dining area. Works best on Victorian/Edwardian terraces where the side return is otherwise wasted space.
A wraparound extension (rear + side) usually exceeds PD limits and requires full planning permission. Worth the effort — wraparounds unlock large open-plan kitchens in narrow Victorian terraces.
Budget £2,200–£3,500 per m² for London build costs (2026). So a 25m² rear extension is £55,000–£87,500 to build, plus our fees and council fees. We coordinate trusted builders.
Fixed fee from £1,225. Free quote in 60 seconds. Covers every London borough.
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