We typically use a Sarnafil singly ply membrane for areas of flat roofs, this is BBA certified to have a life expectancy of over 40 years.
Sarnafil is widely recognised as being the pre-eminent flat roofing system. It is undoubtedly technically and aesthetically superior to any alternative synthetic solutions such as glass fibre or rubberised membrane, and is leagues above traditional torched-on felt. It has been used on widely in the commercial sector for many years, on many prestige projects such as the Emirates Stadium, Bluewater Shopping Centre and Stanstead Airport. Click here to visit their web site for further information and reference projects.
A lead effect colour is normally used, and Sarnafil is generally accepted to be neater and more durable than lead itself, but at a fraction of the cost. Lead and other metal trims are used for flashings and detailing.
We design our flat roofs to have minimal falls, typically 1 in 80, however Sarnafil is unaffected by standing water and can be laid completely flat. Box gutters are usually designed to be perfectly level and will therefore hold water. Similarly, some orangery roofs may incorporate level sections, particularly near the outlets but this does not present a problem. In their product guarantee, Sarnafil state “Sarnafil membranes provide maintenance free roofs which are unaffected by standing water, accumulations of dirt or normal airborne concentrations of chemicals.”