Having built up a successful business selling PVCu windows, Synseal’s founder Gary Dutton switched to manufacturing in 1990. In 1995 he sold the assembly side to JBS Industries for a reported £3.2m. The company now makes only sections of PVC sold to window and conservatory makers. Synseal claims to make parts for 2,000 conservatory roofs a week at its 30-acre site in Nottinghamshire. A greater range of products and economies of scale have helped profits grow 51% a year from £3.7m in 2001 to £12.8m in 2004.