Basement conversion in North Kensington

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

RBKC’s 2021 designation map shows the Oxford Gardens - St Quintin conservation area designated in 1975 and extended in 2002 and 2021, the latest phase along Latimer Road, where a March 2021 RBKC analysis had assessed the traditional terraces between North Pole Road and the Westway. That analysis says the area was first designated in 1975 for the speculative Victorian and Edwardian suburban housing on the Portobello and St Quintin estates. RBKC lists the adopted appraisal in an entry dated October 2021; the street descriptions here come from its October 2018 consultation draft.

The 2018 draft attributes houses in Bassett Road and the western parts of Oxford Gardens and Cambridge Gardens to Henry Currey, architect to the landowner Colonel St Quintin, built between 1867 and 1890 and fronted in pale gault brick, with yellow stock brick to the sides and rear. There, Oxford Gardens is almost entirely double-fronted detached houses, Cambridge Gardens has generously spaced villa pairs and Bassett Road a mixture. Where Oxford Gardens and Cambridge Gardens continue east of Ladbroke Grove, the draft describes four-storey houses over basements, with larger front gardens, mature trees and only small lightwells.

The draft dates the red-brick Edwardian houses to 1905–1914: mainly long two-storey terraces with large original rear outriggers, most with full-height canted bays and one-over-one sashes, and none built with basements. Cottages and flats in cottage form followed in 1919–1926, designed by the LCC architect A. S. Soutar for the Royal Borough of Kensington. Subdivision is older still: the draft records large houses in the area failing to attract wealthy owners and starting to be divided in the 1880s.

Local design and consent context

Direction 88 is a Hammersmith and Fulham direction dated 13 November 1979 that RBKC still lists. At 1–55 (odd) Brewster Gardens and 2–56 (even) Bracewell Road it removes rights for all rear extensions, rear roof extensions included, and for buildings or structures within the curtilage.

Policy C2, in the streets and part streets covered by Directions 46 and 62, supports minor ridge-height changes for insulation that do not materially affect the roof’s appearance or create an uneven terrace roofline, and requires main chimney stacks to be kept; C3 resists non-permeable front-garden surfaces above the permitted development limits; C4 makes no requirement for a set-back where a ground-floor rear or side extension takes in the original side passage; C5 resists such extensions that are over 3m high at the party wall, have a roof slope over 45 degrees or infringe neighbours’ rights of light; C6 seeks to limit rear-garden outbuildings to 12 square metres of coverage, with 2.5m eaves and a 3m ridge; and C7 asks for discreet bin stores, flues, dishes and meter boxes on house fronts where permission is needed. Ask RBKC how these sit with the Local Plan 2024 for your proposal.

For basements, one direction covers the whole of Kensington and Chelsea. RBKC made it on 15 April 2015 and confirmed it on 2 March 2016, and since it came into force on 28 April 2016 there have been no householder permitted development rights for basements, lightwells or any other development below the dwellinghouse or its curtilage.

Access and site planning

A resident parking bay can be suspended only on at least 10 full working days’ notice, and RBKC asks for any suspension to be applied for before the licences themselves. The applicant for a highways licence must be a registered company; RBKC reviews each application within 10 working days of payment, and nothing may start on the street until it has given written approval. Scaffolding and hoardings count as temporary structures, licensed three months at a time, while a skip on the road needs a licence issued for a month at a time, and roll-on, roll-off storage containers are not allowed anywhere in the borough.

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

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