Basement conversion in Dulwich

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

Dulwich Village Conservation Area was designated in September 1968, one of the first in Southwark. It was extended in September 1971 to land south of College Road and Dulwich Common, and on 15 March 2005 to take in playing fields, part of Village Way and Red Post Hill up to North Dulwich station, and streets north of Dulwich Park including Court Lane, Court Lane Gardens, Woodwarde Road and Dovercourt Road. The appraisal describes a mainly residential area with shops, restaurants and a village pub at its heart, built mostly of red-brown or yellow stock brick under slate or tile roofs.

Street by street the appraisal finds real variety. The tight grain of Pickwick, Aysgarth and Boxall Roads contrasts with the spacious Edwardian and Arts and Crafts houses of Burbage Road, and many of the houses fronting College Road are listed and set well back in large private gardens. Between Court Lane, Woodwarde Road and Lordship Lane stand mostly turn-of-the-century terraces or substantial semi-detached pairs, chiefly brick, often with bay windows and barge-boarded gables. Dekker Road has small cottages and two-level maisonettes, and 1 to 12 Roseway with 157 to 175 Turney Road form a small 1920s garden estate.

West Dulwich is split. On the Southwark side, West Dulwich Station and 136, 138 and 140 Thurlow Park Road fall inside the Dulwich Village Conservation Area. On the Lambeth side, the Park Hall Road Conservation Area is a row of mid-19th-century villas at 33 to 61 Park Hall Road, with semi-basements, stock brick walls, slate roofs and stucco only on the fronts. East Dulwich, in the 2013 SPD’s words, is mostly residential with lots of Victorian terraced housing; none of the five conservation areas that SPD names carries the East Dulwich name.

Local design and consent context

Southwark’s Dulwich Village Conservation Area Appraisal is dated February 2006 and published in three parts. It divides the area into five sub-areas, from Dulwich College and the Picture Gallery to the old village, Court Lane and North Dulwich Station, and says that once adopted it is a material consideration on planning applications. Its guidelines ask you to consult the council’s conservation officer before altering the outside of any building, and they rule out losing front gardens to car parking or grass verges to crossovers.

The Southwark Plan 2022 was adopted on 23 February 2022 and covers 2019 to 2036. The Householder Development SPD, adopted by cabinet on 7 July 2025, applies to houses and flats, including listed buildings and homes in conservation areas, and guides the use of the plan’s policies without adding new ones. It encourages rear extensions to stay single storey, requires a Basement Impact Assessment with any basement application, limits basements to one storey below ground and permits lightwells only where they are already a common feature of the street or area.

For an address on Lambeth’s side of West Dulwich, the plan in force is the Lambeth Local Plan 2021, adopted on 22 September 2021; the council is preparing a new plan, but until one is adopted the 2021 plan stands. Lambeth’s Design Guide SPD of 8 August 2023 deals with alterations, extensions and retrofit in Part 4 and with basements in Part 5. Part 4 generally backs rear dormers, but on a front roof pitch it resists them unless they are characteristic of the building type or group. For Nos 33 to 61 Park Hall Road, the 2016 statement resists front dormers and front or flank extensions, and asks for single-storey extensions that do not dominate the villa.

Access and site planning

The address decides which council’s street rules apply. Southwark takes skip licence applications from skip companies alone, and they must arrive 7 days before delivery; a skip in a restricted parking space also needs a bay suspension, booked with seven days’ notice. A scaffold or hoarding on or over a Southwark highway needs its own licence, applied for 15 working days or more before the start. Storing materials on the highway needs a separate licence. Lambeth likewise licenses skips through skip companies, covers scaffolding, hoarding and stored materials with a highways licence, and wants 10 or more working days’ notice for a standard suspension.

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

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