Flat Roofing in Southampton
Flat-roofed rear extensions are extremely common across Southampton — particularly on the Victorian and Edwardian terraces in Portswood, Bevois Valley and St Denys, where single-storey kitchen extensions were added throughout the 20th century. The 1960s council-built properties in Thornhill and Lordshill also feature large areas of flat roof on single-storey outbuildings and side extensions.
GRP Fibreglass Flat Roofing
GRP (glass reinforced polyester) is a seamless, fully waterproof system that is ideal for Southampton's damp maritime climate. There are no joints or seams for water to penetrate. Once laid, it is virtually maintenance-free and carries a manufacturer-backed guarantee. It handles the UV exposure Southampton roofs receive in summer and the wet conditions in winter equally well.
EPDM Rubber Roofing
EPDM single-ply rubber membrane is our preferred choice for larger flat roof areas — particularly on extensions over 30 square metres. It is flexible, highly resistant to UV and moisture, and performs exceptionally in the temperature range Southampton experiences throughout the year. A professionally installed EPDM roof will outlast the building it sits on.
Flat Roof Replacement on Southampton's 1960s Stock
The post-war and 1960s estates in Thornhill, Lordshill and Weston have a significant volume of felt flat roofs that have been repaired and patched over decades. At this point, replacement with a modern system is substantially cheaper over a 10-year period than ongoing felt repairs. We assess, advise and quote honestly.
Flat Roofing Costs
Small extension (under 15m²): £900–£1,800 · Medium extension (15–30m²): £1,800–£3,500 · Large garage or extension (30m²+): £3,500–£6,000. Costs depend on area, material, access and condition of existing deck.