Roofs offer protection from the elements, but can also help exploit ambient energy sources and sinks, contributing to the space heating, cooling, ventilation and daylighting of buildings (Figs 1.1-1.2). The mainstream approach to roof design has emphasised the roof’s protective function. This includes protection from sun, ambient temperature, wind, rain and snow. In most European countries building regulations enforce a prescriptive application of thermal insulation as a means of reducing the use of energy for space heating and cooling.