Loft conversion in Northwood

Test the roof space before settling on a layout.

Start with the loft conversion brief

A measured roof survey should establish headroom, structural spans and where a staircase could meet the floor below. Plan the stair, escape route, insulation and building services together before treating the loft as another room.

Compare the proposed roof shape with the address-specific design guidance below. Record chimneys, shared walls and neighbouring rooflines, then ask the appointed designers to identify the structural work and consents the proposal needs.

The local building context

Hillingdon’s Northwood Town Centre, Green Lane Conservation Area Appraisal, adopted in September 2019, describes a relatively small conservation area centred on the Green Lane and Maxwell Road junction, taking in Station Approach and most of the residential Maxwell and Murray Roads. Green Lane was a quiet country lane until Northwood Station opened in 1887; by 1891 Frank Murray Maxwell Hallowell Carew had laid out the roads, naming them after himself and his family, and sold all the plots. The historic buildings are mainly red brick under red clay tiles, with gables, half timbering, sash windows, leaded lights and chimney stacks.

Hillingdon’s November 2009 leaflet describes the Northwood-Frithwood conservation area, designated in 1989, as primarily large, individually designed detached houses in the Arts and Crafts style on the estate Frank Carew developed after the Metropolitan Railway arrived in 1887, with later houses by C.H.B. Quennell, Swanell and Sly and John Markham, on roads lined with mature trees. Hillingdon’s local list includes Quennell houses of about 1910 at 5 Carew Road, in red brick under a sweeping tiled hipped roof, and a line of his houses at 10–16 Eastbury Road.

The Glen, a conservation area since July 2007, is a 1950s planned estate of maisonettes on the south side of Green Lane, designed by Kenneth C. Saunders, Architects, and built in 1958 and 1959 in brown brick, with white-painted casements and brown tiled roofs with bonnet hips. Hillingdon’s Area of Special Local Character maps for the Copsewood and Gatehill Farm estates take in Copse Wood Way, Nicholas Way, Gatehill Road and Elgood Avenue; the 2023 townscape study illustrates its large suburban type with Nicholas Way, describing substantial houses on large plots, many with a strong Arts and Crafts influence.

Local design and consent context

Hillingdon has 15 Areas of Special Local Character, which it describes as non-designated local heritage assets. Its list includes Dene Road, Northwood (13 November 1989), Old Northwood (31 March 2005) and Hillside, Northwood Hills (24 July 2008), and gives the Copsewood Estate and the Gatehill Farm Estate, Northwood, a designation date of “Not applicable”. Policy DMHB 5 asks alterations in these areas to respect the established scale, building lines, height, design and materials, and extensions to be subservient, leaving space for landscaping.

Local Plan Part 2 has special policies for the Gatehill Farm Estate and Copse Wood Estate: new development is expected to conform to the vernacular styles predominant there, with traditional roof forms and architectural features, and to relate to its landscaped setting. Policy DMHB 6 asks new houses there to keep similar plot widths and building lines, unobtrusive boundaries in natural materials, at least 1.5m to side boundaries and the mature trees. Under Policy DMHD 1, two-storey side extensions there should be set in at least 1.5 metres from the side boundary, and most Copse Wood Estate trees carry preservation orders.

Hillingdon lists five Article 4 directions, none of them a conservation-area direction for Northwood householders. The one that reaches ordinary house extensions is borough-wide: in force from 22 September 2014, it removes permitted development rights for a single-storey rear extension reaching more than 4 metres beyond the rear wall of the original house. The sealed direction is dated 20 September 2013 and was confirmed on 22 July 2014.

Access and site planning

Plan deliveries, waste storage and protection for any shared hall, stair or drive before work starts. For a Hillingdon address, a skip on a public road needs a permit, which the skip company obtains, with any exemption from Parking Services first where parking restrictions apply; a scaffold on a road, verge or footway needs a council licence, applied for by the scaffolding contractor with at least 10 working days’ notice. Suspending a parking bay for building works needs 5 full working days’ notice for pay and display bays and 7 for permit holder bays.

Continue planning

The Northwood area guide · Loft conversion across London · Hampstead Architecture & Planning · Hampstead Chartered Surveyors

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