Basement conversion in Hadley Wood

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

Enfield’s Hadley Wood Conservation Area Character Appraisal places Hadley Wood in the north-western corner of the borough and describes it as essentially the creation of Charles Jack, then tenant of Beech Hill Park, who part-funded the new station. Designated in 1989, the conservation area covers 13.4 hectares at the centre of Hadley Wood, with 75 houses and a church. Its heart is the horseshoe of Crescents East and West off Camlet Way, with Lancaster Avenue branching north-east from Crescent East, and the railway cutting and a parade of modern shops effectively divide it in two.

The appraisal sets out three house types by building phase. Crescent West, built first, has tiled roofs, tile-hung upper floors, paired canted bays, large dormers and timber casement windows; Crescent East has mostly linked pairs with slate roofs, red brick facades, offset gables and timber sashes; and Lancaster Avenue, built last, has rendered upper storeys, paired façades and slate roofs. It singles out the joinery, decorative brick aprons and stained glass, and a terrace of white-rendered cottages at 34–40 Crescent West. Extensions are typically side wings or garages, subservient to the houses.

Across the wider neighbourhood area, the made Hadley Wood Neighbourhood Plan describes a suburban settlement of mostly two-storey buildings, some with rooms in the roof. It names ‘Elizabethan style’ houses in white render and black timber on Lancaster Avenue and Parkgate Avenue, an estate of bungalows on Covert Way and detached homes on large sites along Camlet Way. Since the early 2000s, large detached houses on Cockfosters Road, then Beech Hill and Camlet Way, have increasingly been replaced by mansion-style apartments, and the plan records no building with more than four floors of habitable space above ground.

Local design and consent context

Planning Data records the Hadley Wood Conservation Area, reference CA11, as a London Borough of Enfield conservation area, and the appraisal gives 1989 as the year of designation. Enfield, which has 22 conservation areas, lists four documents for this one: the character appraisal, the management proposals, the 2006 Article 4 Directions and the Article 4 map.

The character appraisal was first adopted in 2006, reviewed in February and March 2013, approved in February 2015 and amended in September 2016 to take account of Douglas Close, the development behind 29–33 Lancaster Avenue. The management proposals, approved in February 2015, confirmed the boundaries after a review in October 2013 and aimed at five-yearly reviews. Neighbourhood Plan policy HW-5 says applications in the conservation area, or affecting its setting, must have regard to both documents, and that development should take opportunities to protect and, where appropriate, restore original features such as walls, windows and doors.

Its policies reach everyday house projects. HW-12 asks for extensions subsidiary to the host building, dormers inset at least 500mm from the eaves, ridge and edges of the roof, and rooflights on less prominent slopes, and says uPVC doors, windows and rainwater goods will not generally be supported in the conservation area. HW-1 asks development to keep at least 1m from side boundaries, and HW-2 and HW-3 say front boundaries over 1m need planning approval and that new or replacement hardstanding must leave at least a quarter of the front garden unpaved, unless individual circumstances make that inappropriate.

Access and site planning

For an Enfield address, the council says noisy building work that can be heard at the site boundary should only take place Monday to Friday, 8am to 6pm, and Saturday, 8am to 1pm, and is not allowed outside these times or on bank holidays unless agreed with the council in advance; the Neighbourhood Plan repeats those hours. Check the lease and any rules the building manager sets on noise and deliveries. If you will live at home through the work, decide which rooms stay usable and when water or power will be off, and tell neighbours what is planned and when.

Continue planning

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

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