Curtain wall systems are typically designed with extruded aluminum members, although the first curtain walls were made of steel. The aluminum frame is typically infill with glass, which provides an architecturally pleasing building, as well as benefits such as daylighting. However, parameters related to solar gain control such as thermal comfort and visual comfort are more difficult to control when using highly glazed curtain walls.
Other common infills include: –
Stone Veneer, Metal panels, Louvres, and Operable windows or Vents.
A Curtain wall is which encloses the space within a building but does not support the roof.
Curtain walls differ store-front systems in that they are designed to span multiple floors, and take into consideration design requirements such as:-
Thermal Expansion and Contraction; building sway and movement; water diversion; and thermal efficiency for cost-effective heating, cooling and lighting.
The Curtain wall systems are a non-structural claddding systems for the external walls of buildings. They are generally associated with large, multi-storey buildings.
The classification of types of curtain walling varies but the following terms are commonly used:-
Stick, Unitised, Panellised, Spandrel panel ribbon glazing, Structural sealant glazing, Structural glazing.
The general arrangement of a stick system curtain wall is:-
Horizontal and Vertical framing members(‘sticks’) are normally extruded aluminum protected by anodizing or power coating, but may be cold-rolled steel (for greater fire resistance) or aluminum Clad with PVC-U. Members are cut to length and machined in the factory prior to assembly on site as a kit of parts: Vertical mullions, which are fixed to the floor slab, are erecteds first followed by horizontal transoms, which are fixed in-between mullions. Mullions are typically spaced between 1.0 and 1.8m centers.
The framework are fixed infill units, which may comprise a mixture of fixed and opening glazing and insulated panels (which may have metal glass or stone facings). These units are typically sealed with gaskets and retained.
Building were constructed with the exterior walls of the building (bearing walls, typically masonry) supporting the load of the entire structure. The development and widespread use of structural steel and later reinforced concrete allowed relatively small column to support large loads and the exterior walls of building were no longer required for structural support.
The exterior walls could be non-load-bearing and thus much lighter and more open than the masonry load-bearing walls of the past. This gave way to increased use of glass as an exterior facade, and the modern-day curtain wall was born.
Early prototype versions of curtain walls may have existed in buildings of timber construction before the nineteenth century, should columns have been used to support the building rather than the walls themselves, particularly when large panels of glass infill were involved.
When iron began to be used extensively in buildings in late 18th-Century Britain such as at Ditherington Flax Mill, and later when buildings of wrought iron and glass such as The Crystal Palace were built, the building blocks of structural understanding were laid for the development of curtain walls.