Curtain Walling is defined in the Building Construction Handbook by Chudley and Greeno, as a form of lightweight non-load bearing external cladding which forms a complete envelope or sheath around the structural frame.
The concept of the fully glazed wall has been architectural idea for a long time, only awaiting the necessary technology to become a reality. The King’s College Chapel in Britain built in 1829 took windows to the point of forming virtually the entire wall that was not needed for roof support.
Today, curtain walls are used extensively, particularly in large commercial buildings.
Types of Curtain Walls
The two basic types of curtain walling systems are:
Stick Curtain Wall Systems
These consist of many mullions or sticks that are installed in a structure after being prepared at the factory. Once the sticks are in place, the vents, spandrels and glazing panels are fixed in the form of a grid. The stick system is economical and reliable, if correctly installed. However, this system is time-consuming and may not be suitable for urgent projects.
Unitised Curtain Wall Systems
This includes installation of many factory-assembled frames with interlocking transoms and mullions. This type of curtain walling can be done quickly with minimum labour needed on-site and low installation expense. However, shipping costs, careful handling and costly lifting equipment are some of the drawbacks of the unitized curtain walling system.
Materials Used in Curtain Walls
All materials of walls prevent noise pollution and provide security to the people inside a building. Curtain walls give a building aesthetic appeal and a uniform look. However, different materials used in the building have their separate benefits and drawbacks.
The contemporary glass curtain walls are known for their aesthetic appeal and modern look. Glass is suitable for wall high-rise buildings and gives off various tones of colour under the sun and the moon adding to the beauty of the area. However, glass can cause light pollution and can get dirty due to rain or dust in the air. Also, extensive research is required to install glass with emphasis on type of glass, thickness, shape etc.
Glass helps natural light into the building and reduces solar heat gain as well as lighting requirements in the day. Many fire-resistant glass sheets are available that help in protecting the building from fire. It also provides for thermal insulation which allows the heat or the cooling to stay inside the building.
Aluminium has been extensively used for curtain walling purposes due to its features of being lightweight, water-proof and corrosion resistant. It gives an elegant look to the exterior of a building. However, the type of aluminium sheets used should be according to building and weather standards.
The drawbacks of having curtain walls are that it needs regular maintenance. A sealant is applied to the wall perimeter, which requires replacement after more or less, every decade. Moreover, installation costs and the wall itself are quite expensive and require heavy investment.
Overall, these walls are great if they are designed and installed correctly into the structure and are maintained after regular intervals of time. MBD