Curtain walls are one of the most critical but increasingly expensive elements of high-rise buildings. Architectural and functional requirements require the search for new building solutions. The need to use curtain wall systems at increasing heights also creates great difficulties.
A bit of history about curtain walls
The curtain wall made of aluminum and glass dates back to the early 20th century. In 1906, architect Francis Plim designed two copper profiles to hold the glass firmly. The profiles also had holes for water drainage and pressure equalization. This decision marked the beginning of the use of facade structures that bring more light and air into the building’s interior. In 1930, the first thermal break aluminum profiles were created. The glass production method has also changed: in addition to high strength, it has acquired better thermal parameters and a wide range of colors.
Lightweight curtain walls began to be used around the turn of the 1960s. However, lightweight baffles have often been unsuccessful; In summer, the rooms were overheated; it was too cold in winter. The frame of the structure rusted, and the insulating materials were worn out.
The beginning of the nineties was a real breakthrough in the use of aluminum facades. High availability and a wide choice of materials, massive demand for durable, aesthetic fronts with large glazed surfaces – these are the factors that have led to the rapid development in the field of metal and glass curtain walls.
Curtain walls in multi-story buildings – expectations and requirements
Examples of skyscrapers with curtain walls: Petronas Towers in Kuala Lumpur, height 452 m, or Financial Center in Taipei, height 508 m. These investments are not mentioned by chance. They have been implemented in tropical climates. This means that phenomena such as overheating or creep in joints will double the force.
The most critical issues to consider when designing the smallest details of a curtain wall:
Curtain wall design solutions
Among the wide range of design solutions, the most important in current projects is the solution to the problem of joining the glass that makes up the exterior of the building, with the rest of the structure of the facade and building.
The building’s upper texture should have a smooth surface, without scratches at the joints of individual facade panels, without accessories. It should also be easy to wash.
Modern building joints are invisible fixings that do not interfere with the smoothness and uniformity of the facade. They are also durable, UV and heat resistant, as well as relaxing and creeping effects.
Considering such criteria as functionality, technical parameters, and visual value, walls from the group of structural and semi-structural glazing systems are the most technically advanced.
Architects and investors strive to hide the wall mount as much as possible; thus, a wide range of point-to-point connections have entered the market. The joint supporting the outer facade cladding must be small, strong, safe, heat and freeze resistant. It must also be invisible.
An example of an interesting and increasingly popular solution for a point curtain wall made of aluminum and glass is the Exchange Center building.
Another example is the facade of the building of the “Focus” insurance company; The solution used in this building is not only one of the first applications of point connections, but also an impressive achievement – in terms of glass span and, therefore – the high bearing capacity of point connections supporting such huge and heavy glasses. This solution has become a model and a symbol of modernity in aluminum facades’ joints and received the nickname “Mega Windows”.
Point joints on the market and equated to modern solutions are still mechanical joints that require glass processing (cutting, drilling, edging). They require screwing on the construction site and interfere with the smoothness and cleanliness of the outer coating.
Attempts to modernize point connections lead to the maximum possible masking of the fittings. There are various tests for point fixing of wall coverings.
Currently, there are projects on the market in which mechanical joints are replaced by adhesive bonding. However, in many situations, mechanical connections have a supportive or protective function.
From the literature and examples of European and world construction, it is known that modern building materials provide the possibility of using only adhesive joints as the main load-bearing elements when connecting the external cladding of metal glass facades.
Requirements for curtain walls in the post-transom structure
Curtain wall specifications apply to individual wall components (including, for example, facade textures) as well as curtain walls as an end product. Facade texture has three main tasks:
The structure also performs several other functions necessary for the proper functioning of the facility:
You should also pay attention to the structure’s features during its production cycle (duration of the production process, ease of execution, consumption of materials, and energy). The most important characteristics have a decisive influence on the texture’s durability during the building’s operation and its interaction with the external partition.
