The curtain wall is the most airtight and weather resistant cladding and exterior wall system available. This article provides an overview of the components of modern glass and aluminum curtain walls, their design features, performance and durability characteristics. It also provides the architect or designer with knowledge of the technology of curtain wall design with respect to air leakage control, rain penetration control, heat loss (or gain) control and condensation control. Consideration is given to testing of a new curtain wall system design. This article also provides sample design details of curtain wall connections at grade, soffits, head and sill conditions, parapets and at connections with other cladding and wall systems such as brick or precast exterior cladding and wall systems. This article does not review the structural design of aluminum curtain walls systems nor does it review storefronts, sloped glazing or skylights.
The glass and aluminum curtain wall is found in city centres on many new buildings and it is quite popular as a cladding and exterior wall on all types of commercial, industrial, institutional and residential buildings. The curtain wall is characterized with coloured vision and spandrel glass areas, a grid of aluminum caps and most recently with metal or stone spandrel covers. It is also combined with other types of cladding systems such as precast, brick or stone to create attractive and durable building facades. The curtain wall comprises a complete cladding and exterior wall system with the exception of the indoor finishes. It is generally assembled from aluminum frames, vision glass and spandrel glass (or metal or stone) panels to enclose a building from grade to the roof. It is available in three system types to include the stick built system, the unitized (or panel) system and the structural glazing system (capless vertical joints). The glass and aluminum curtain wall is designed to resist wind and earthquake loads, to limit air leakage, control vapour diffusion, prevent rain penetration, prevent surface and cavity condensation and limit excessive heat loss (or heat gain). It is further designed to resist noise and fire.