Basement conversion in Grange Park

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

The appraisal, approved in June 2015, places the conservation area south-west of Enfield Town, midway between the town and Winchmore Hill, in the valley between the railway embankment and Bush Hill, with golf courses and open space along both long sides. The estate took its name from Old Park Grange, or Pike’s Farm, demolished in 1913. The builder Richard Metherall, who had built in Muswell Hill, bought the land, and Grange Park station was built in return for his deal with the railway company: an exchange of land and an agreement to build a certain number of houses for commuters.

The appraisal describes three principal roads: The Chine and Old Park Ridings, which run mainly north to south across the Salmons Brook valley and rise steeply towards Old Park Avenue and Green Dragon Lane, and The Grangeway, which crosses them at the lowest point. Houses at the northern ends, built in 1913–14, are mainly detached and larger than those in the southern parts, with a similar Arts and Crafts influence; the inter-war semi-detached houses in the central parts have two-storey bays with half-timbered gables, plain casements and porches. Three parades of shops with flats over line the western Grangeway.

In the conservation area, houses are closely built and, except at the northern end of The Chine, stand on narrow plots; towards its top, nos. 99–127 (odd) and 90–98 (even) are substantial detached houses on more spacious plots. In the southern part of The Chine, windows are sashes, or casements in horizontal ranges with stone mullions, sometimes with leaded lights. The appraisal finds the houses’ character largely intact apart from uPVC replacement windows, mostly fitted before designation, and records front gardens paved for parking and walls, fences and hedges lost, with Old Park Ridings suffering particularly.

Local design and consent context

Planning Data records the Grange Park Conservation Area, reference CA19, as a London Borough of Enfield conservation area, and the appraisal says it was designated on 5 November 2008 and that its boundary has remained unchanged. Enfield, which has 22 conservation areas, links four documents for it: the character appraisal, the management proposals, the 2008 Article 4 directions, which also cover the Meadway and The Crescent conservation areas, and an Article 4 map.

The character appraisal and the management proposals were both approved in June 2015, and the proposals confirmed the boundaries after a review in July and August 2014; Enfield’s Grange Park page lists no other documents. The appraisal finds that the area’s tightly planned layout, houses in single occupation and green setting of trees and gardens offer minimal scope for major change and redevelopment, or even for side extensions.

For those houses, the direction withdraws permitted development rights for enlargements and alterations, roof-slope alterations and porches fronting a highway, open space or waterway; outbuildings, pools, oil or LPG heating tanks and hard surfaces fronting one; chimneys, flues and soil and vent pipes; microwave antennas fronting one; front gates, fences and walls, including their demolition; and exterior painting fronting one. Each then needs a specific planning application; the management proposals sum up the effect as needing planning permission to change windows, doors and roof coverings, to paint or render brick facades and to build, alter or demolish a front boundary.

Access and site planning

Enfield 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. In a flat or maisonette, check the lease and any rules the freeholder or managing agent 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 Grange Park area guide · Basement conversion across London · Hampstead Architecture & Planning · Hampstead Chartered Surveyors

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