Builders in North Harrow

Before North Harrow station opened on the Metropolitan line, the area was known as Hooking Green. The suburb that grew around the station between the wars, together with neighbouring Rayners Lane, is made up of street after street of semi-detached houses built to a small number of designs, with hipped roofs, bays and side passages.

The 2021 Census shows how uniform it is. In North Harrow, Rayners Lane North and Pinner Road, 67% of households lived in houses and 46% in semi-detached houses, one of the highest shares of any area we cover. Median semi-detached prices in those areas were about £680,000 to £745,000 in the year to March 2026.

Because the houses are so similar, your street is a good guide to what works. Many neighbours will already have a hip-to-gable loft conversion or a rear kitchen extension, which helps both the design and the planning case.

Harrow's Residential Design Guide prefers exactly this kind of loft conversion for semi-detached houses: a hip-to-gable with a rear dormer. If planning permission is needed, the dormer should be set in at least 0.5 metres from the party wall and 1 metre from the gable end, and set back at least 1 metre from the eaves measured along the roof slope. Many semis can do the work under permitted development instead, within 50 cubic metres.

The Rayners Lane and Pinner Road conservation areas, both part of Harrow's Pinner group, are close by. Check whether your street is included, as permitted development rights are reduced inside them.