Loft conversions in Barnet

Barnet's roof guidance

• Hip-to-gable: often possible under permitted development; if not, generally acceptable where it rebalances a pair of semis whose other half already has a gable, or a short terrace whose end house has one.
• Rear dormers: permitted development where rights exist; otherwise inset at least 0.5 metres from the eaves, ridge and edges of the original roof.
• Side dormers: set at least 0.5 metres up from the eaves, clear of the hips, and obscure-glazed up to 1.7 metres.
• L-shaped dormers: permitted development over an original outrigger where rights exist; otherwise, where they are typical locally, covering no more than half the outrigger's depth and set down 0.5 metres from the main ridge.
• Front dormers: generally not supported unless they are already common in the street.

Materials

Barnet expects dormer cheeks in lead, tiles, slate or similar traditional materials, flat dormer roofs in lead or zinc, and no roofing felt on the roof, cheeks or face. Windows should match those on the house.

Conservation areas and the Garden Suburb

Roof enlargements aren't permitted development in Barnet's 16 conservation areas, and in Hampstead Garden Suburb a loft conversion also needs the Suburb Trust's consent. Where Building Regulations headroom means a dormer can't be set down from the ridge, Barnet asks for a section drawing showing the internal ceiling heights.