Exterior wall type speaks to what is exterior wall type and why use exterior wall type for both the loadbearing and the curtain wall.
Until the late nineteenth century nearly all large buildings were built with loadbearing exterior walls. These walls supported a substantial portion of the floor and roof loads of the building, as well as separating the indoor environment from the outdoors.
In non-combustible buildings, these walls were built of brick or stone masonry. Functionally, such walls had several inherent limitations. They were poor thermal insulators and they were heavy, requiring large foundations and limiting their height to a few stories.
The loadbearing wall has been brought up to date with higher strength masonry and concrete. Components such as thermal insulating materials, cavities, flashing, air barriers and vapor retarders have been added to make the wall more resistant to the passage of water, air and heat. Also the addition of steel reinforcing has allowed the wall to become thinner, lighter and better able to resist wind and seismic loads.
Loadbearing masonry and concrete exterior walls and concrete exterior walls are often attractive and economical for low and medium rise buildings. High rise residential towers with exterior loadbearing masonry walls also continue to be built, especially in Asia.
The first steel framed skyscrapers, built in the late nineteenth century, introduced the concept of the curtain wall, an exterior wall supported at each story by the frame. The name “curtain wall”, an exterior wall supported at each story by the frame. The name “curtain wall” derives from the idea that the wall is thin and hangs like a curtain on a structural frame.
Most curtain wall panels do not actually hang in tension from the frame but are supported from the bottom at each floor level.
The earliest curtain walls were constructed of masonry with the principal advantage of the curtain wall is that, because it bears no vertical load, it can be thin and lightweight regardless of the height of the building. Compared to a masonry loadbearing wall, a curtain may become prohibitively thick and weighty at the base of a very tall building.
Curtain walls may be constructed of any non-combustible material that is suitable for exposure to the weather. They may be either constructed in place or prefabricated. Other curtain walls are constructed of masonry and concrete and metal and glass. Some are constructed in their place and others are prefabricated, but all are supported by the frame of the building.