Wind Loading- care is needed in design to prevent water ingress under the positive & negative pressures created by wind movement.

of pressure on the back face. As it is deflected over the roof and round the sides the reduction in pressure creates suction in these areas. Careful design is needed to ensure the integrity of the whole structure and to prevent water ingress. In winds of 110mph and heavy rainfall, equivalent to the worst UK conditions, the BBA gave the roofing system a 25 year life expectancy. Typically, the roof is designed in line with British Standards to support an imposed load of 75 kilogrammes per m² - equivalent to 600mm or 24" of snow in one fall or equivalent of one and a half bags of cement. In remote areas of the Highlands and Islands even greater loads are designed for. The combination of these factors means
that the roof has to be strong, durable and attractive. Each roof is carefully specified from a portfolo of 3500 components, ensuring maximum structural performance. The roof system comprises structural aluminium profiles which have bolted joints rather than poorer quality screws which are often employed. Each structural aluminum profile is then capped and clad with pvc-u; these items are known as thermal cladding and they minimise the formation of condensation.