Basement conversion in Kew

Investigate the structure and ground before design.

Start with the basement conversion brief

Distinguish an existing cellar conversion from excavation for a new basement. Record levels, drainage, access and the adjoining structures, and obtain project-specific ground and structural investigations before relying on a design or budget.

Plan temporary works, waterproofing, ventilation, escape and spoil removal as part of the same brief. Ask Hampstead Chartered Surveyors to assess party-wall matters and Hampstead Architecture & Planning to coordinate the design requirements. An area name alone does not establish ground conditions.

The local building context

Kew Green Conservation Area was designated on 14 January 1969 for the Green and the riverside, then extended in 1982 along the Kew Road approach and in 1988 over the residential streets east of the Green. Its appraisal, adopted on 8 February 2024, finds Georgian houses around the Green and a mainly Victorian Priory Estate to the east, where Forest, Maze, Gloucester and Priory Roads were being built in 1866. The east side of the Green itself mixes cottages, mansion blocks and terraces, and west of Kew Bridge stand 20th-century flats set among riverside greenery and deep rear gardens.

Kew Gardens Conservation Area began in 1969 as the Lichfield Road Conservation Area and lies around Kew Gardens Station; its statement records five extensions, the latest on 9 February 2017. It describes substantial detached and semi-detached villas of two to two and a half storeys in large plots behind continuous walls or railings, built in red or yellow stock brick with timber sliding sashes. Ennerdale Road has three-storey Victorian and Edwardian houses with some infill flats, while the two-storey cottages of Clarence Road, Elizabeth Cottages and Victoria Cottages are small and closely packed.

Lawn Crescent, designated on 17 September 1974 and enclosed by the Kew Gardens area, is a group of two-and-a-half-storey houses in originally tuck-pointed red brick under steep slate mansard roofs. Along Kew Road, the Kew Road Conservation Area has Victorian villas between larger modern blocks, then tighter Edwardian terraces and pairs towards Richmond. In East Kew, Burlington Avenue and West Park Road, and Ruskin Avenue and part of Defoe Avenue, are both areas of paired Edwardian houses. The North Road, Dancer Road and Darell Road terraces sit in the 2014 guidance’s Chilton Road character area, not in a conservation area.

Local design and consent context

The Kew Green appraisal was adopted on 8 February 2024 after consultation from 18 September to 27 October 2023. It reads the area as four character areas, Kew Road, The Green, Riverside and the Priory Estate, and counts 38 listed buildings, 223 Buildings of Townscape Merit and two Grade II listed bridges; the national list includes Kew Bridge and Kew Railway Bridge, both Grade II. It places the conservation area under the buffer zone of the Royal Botanic Gardens, Kew World Heritage Site, inscribed on 3 July 2003, with some parts of the Site itself inside the boundary, and records two Archaeological Priority Areas over it, Kew Gardens at Tier I and Kew Green at Tier 2.

The other Kew areas are described in council statements. Kew Gardens (No. 15) was designated on 14 January 1969 and extended on 7 September 1982, 14 June 1988, 26 October 1998, 27 April 2004 and 9 February 2017; its undated study predates the 2004 direction it proposed. Lawn Crescent (No. 20) dates from 17 September 1974 and Kew Road (No. 55) from 20 September 1988, extended on 23 September 2003. The 2014 guidance says the Kew Road area includes every building fronting Kew Road between Broomfield Road and Christ Church except Nos 234–240, and to the north the Kew Green area also takes in the approach along Kew Road. So check any Kew Road address on the council’s map. To the south, towards Richmond, the Kew Road area adjoins Kew Foot Road (No. 36). The Royal Botanic Gardens area (No. 63) was designated on 29 January 1991, and the two East Kew areas (Nos. 73 and 74) on 9 February 2017.

The Kew Green appraisal explains that the Article 4 directions in its area affect only unlisted houses in single occupation, and only elevations facing a highway, waterway, private street or other public space. The February 1977 direction, which the council’s register lists, covers roof changes including dormers, window changes including removing bay windows, and rendering or painting brickwork at Nos 1 to 21 Watcombe Cottages, Medina Cottage, The Toll House, 1 and 2 York Villas, 1 to 6 Thetis Terrace and 1 to 7 Willow Cottages. The direction dated 17 February 1995 varies by street: at Priory Road (1–59 odd) it covers only hard surfaces, satellite antennae, gates, fences and walls, and means of access; for Cambridge Cottages (1–36), The Green (28–46 even) and Gloucester Road (1–41 and 53–91 odd) it covers enlargement and roof changes among other items, with exterior painting added at Cambridge Cottages and The Green.

Access and site planning

On closely packed streets, such as the cottage rows off Sandycombe Road, plan where a skip, scaffold and deliveries will go before work is booked. A skip on a path or road needs a licence, valid for up to three weeks, that only a registered skip company with public liability insurance can obtain, and a skip in a controlled parking bay also needs a bay suspension. Scaffolding, hoardings and stored materials need a licence issued only after a site meeting with an Inspection and Enforcement Officer, and no licence is granted just because the council has not replied. For a bay suspension, allow at least 10 working days’ notice, the longer of the two periods the council’s page gives; suspensions can be enforced even outside controlled hours.

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The Kew area guide · Basement conversion across London · Hampstead Architecture & Planning · Hampstead Chartered Surveyors

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