Steel Buildings in Europe

Part 1: Architect’s Guide 1 - 28 4 BUILDING ENVELOPE The steel structure of a single storey building generally comprises three principal components: a primary construction (roof beams and columns, with bracing); secondary steelwork, such as purlins and side rails that support the roof panels and wall cladding; and the roof panels and cladding themselves. The roof panels and cladding are generally referred to as the building envelope. The building envelope provides a weather-tight enclosure to the building space. In most cases, it also provides thermal insulation from the exterior environment. The exterior appearance is often a major consideration in the choice of the form of the envelope. The architect must therefore choose a system that balances the demands of sustaining actions such as wind pressure and (on flat or near-flat-roofs) imposed loads, of achieving thermal performance that meets criteria for low energy use, and of producing an appearance that meets the client’s aspirations. A single type of cladding system is often used for both roof and walls. Detailing will be an important element of envelope design. Drainage systems that do not block or leak are essential and the integration of openings (windows and doors) with the cladding must not compromise thermal insulation. A striking example of using coloured profiled sheeting is shown in Figure 4.1. Figure 4.1 Car repair workshop with steel roof and façade