House extension in Dulwich

Connect the added space to the existing home.

Start with the house extension brief

Begin with how the new space will meet the old rooms, garden and circulation. A measured brief should record boundaries, levels, existing drains, neighbouring windows and the parts of the building you intend to keep.

Develop daylight, structure and services alongside the floor plan. Agree which openings and finishes are included, how the existing home will be protected during construction and which decisions need surveys or approval before a quotation.

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.

An SE21 or SE22 postcode, or the word Dulwich in an address, settles nothing about which council decides, which conservation area applies, whether a building is listed or what consent is needed. Dulwich Library at 368 Lordship Lane has an SE22 address yet sits inside the Dulwich Village Conservation Area. Southwark’s SPD describes a West Dulwich shopping frontage on Park Hall Road, a road whose Nos 33 to 61 form a Lambeth conservation area, and Lambeth has its own West Dulwich ward. The Dulwich Estate’s Scheme covers land in Southwark, Lambeth and Lewisham. So start from the house number. Establish which council it falls under, then search that council’s map of conservation areas, the statutory list of listed buildings and the council’s Article 4 pages for it, and, last, the deeds or lease and whatever has been approved at the address before.

Local design and consent context

The Dulwich SPD, adopted on 16 July 2013, covers Dulwich Village, East Dulwich and Herne Hill. It predates the Southwark Plan 2022, having been written to implement the Core Strategy and the saved Southwark Plan, though the council still lists it, so confirm its current weight before relying on it. It sets a presumption against subdividing large properties, treats Dulwich as generally unsuitable for back-land development and warns that roof or rear extensions may need bat information. For Dulwich Wood, designated on 30 September 1985, the council’s list links only a London Gazette notice and no appraisal; Southwark says it is producing appraisals for its 48 conservation areas on a rolling programme.

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

Weekday hours match on both sides of the boundary, 8am to 6pm, but Saturdays differ: Southwark permits noisy works from 9am to 2pm and Lambeth building work from 8am to 1pm, and neither allows Sunday or bank holiday working. Southwark also wants excessively noisy work done in two-hour spells with two-hour breaks, and, for noisy demolition or construction, Section 61 consent applied for at least 28 days before work begins. Put the dates of the loudest stages in a letter to the neighbours and any managing agent, and think early about whether the household stays in.

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The Dulwich area guide · House extension across London · Hampstead Architecture & Planning · Hampstead Chartered Surveyors

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