House extension in Petts Wood

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

Petts Wood grew in the late 1920s and 1930s on the garden suburb principle. The 2025 Chislehurst Road appraisal credits Basil Scruby, who with his architect Leonard Culliford drew up a masterplan for the roads, amenities and plot sizes that remain largely unchanged, and who used covenants on the plots to control building lines, roof heights and materials; roofs then had to be English tiles of natural clay or stone at a pitch of at least 45 degrees. Station Square was laid out in 1928, and building spread from the east side to the west.

The Local Plan’s Petts Wood Area of Special Residential Character holds around 1,500 detached and semi-detached homes on about 112 hectares, bounded by the railway to the north and the Chislehurst Road conservation area to the north-east, and excluding Station Square. Its prevailing 1930s design remains largely intact. The plan singles out front roof lines largely untouched by roof extensions, the symmetry between pairs of houses, low boundaries and visible front gardens, and rear gardens often over 120ft; some houses are by Noel Rees, who designed every building in The Chenies.

Petts Wood has one Area of Special Residential Character, five conservation areas and several Article 4 plans, and which of them applies is settled plot by plot. One name is a trap: the Chislehurst Road conservation area lies at the northern fringe of Petts Wood, not in Chislehurst. The Local Plan’s written ASRC boundary was also drawn before The Covert and The Thrifts were designated in 2022. Nor is a BR5 postcode or the Petts Wood & Knoll ward any guide: the 2021 order that set up Bromley’s 22 wards does not describe their boundaries in its text. Use the council’s interactive map and each Article 4 plan for the exact plot, and only then turn to the title or lease and the planning record.

Local design and consent context

The design guide calls Petts Wood’s ASRC the largest in the borough. As a Local Plan designation, separate from the conservation areas, it falls under Policy 44, which asks development to respect, enhance and strengthen its special and distinctive qualities. The plan’s guidelines for these areas rule out backland development, ask new work to take account of existing front and rear building lines, ask for mature trees and landscaping to be kept wherever possible, and resist proposals that significantly increase hard surfacing in front of houses unless satisfactory landscaping comes with them. The guide names extensions and replacement houses as the main development pressure.

On 25 June 2025 the council adopted appraisal and management plans for Chislehurst Road, replacing the version of 2000, and for The Covert and The Thrifts. The Chislehurst Road plan prefers rear extensions that do not dominate the house or take up large amounts of side or front space, discourages mass-produced uPVC doors and windows, says the neo-vernacular houses are well adapted to dormers but that in other cases dormers will be inappropriate, particularly on prominent front or side rooflines, and encourages keeping open-plan front gardens. The Chenies and Station Square have no appraisal online; the council says guidance is available on request.

Since 16 January 2019 the statutory Development Plan for Petts Wood, as for the rest of Bromley, has been the Local Plan, used together with the London Plan. Policy 6 looks for extensions whose scale, form and materials respect or complement the house, and dormers that suit the roofscape; Policy 8 asks, as a rule, for a clear metre to the side boundary where a proposal has two or more storeys. The council’s Urban Design Guide, a supplementary planning document adopted on 5 July 2023, offers guidance only and sets no new policy. The plan is under review, with a second Regulation 18 consultation held from July to September 2025; none of that is adopted policy.

Access and site planning

Any skip placed on the public highway needs Bromley’s temporary highway licence, for which only a skip company on the council’s register may apply, and each licence lasts two weeks. Only on a private road with restricted or controlled public access is no licence needed; where the public may pass along an unadopted highway, one is still required. Scaffolding that obstructs the highway, or a hoarding that reaches the footway or carriageway, needs the council’s consent. Apply for a parking bay suspension no later than three working days before it is needed.

Continue planning

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

Discuss your project

Tell us what you are planning in Petts Wood

Share the property location, the work you have in mind and any drawings or permissions you already have.

£5M public liability, £10M employers’ liability and contractors’ all risks cover.

Design support: Hampstead Architecture & Planning.
Surveying support: Hampstead Chartered Surveyors.