A curtain wall plays an important role in modern construction. It can provide a visually pleasing and functional method of separating spaces. In this blog, we will understand the purpose, types, components, and installation of curtain walls and also address the advantages and disadvantages caused by using curtain walls in construction.
What is a Curtain Wall in Construction?
A curtain wall is a thin wall or separating element that is attached to the outer section of the building. These walls help in providing a separation between a building and the environmental forces acting on it. It is important to know that exterior curtain walls do not provide any structural support for the building floors or roofs. Curtain walls are mainly used to prevent moisture and air from reaching the interior of the building. They are generally made of glass with some sort of metal framework.
Curtain walls are normally used in high-rise buildings, commercial properties, as well as modern residential buildings. These are normally made from lightweight materials like metal, glass, or aluminium. Curtain walls can be used for multiple floors and improve the exterior appearance of the buildings. Even if they have a delicate appearance, certain walls are durable and provide protection against external weather elements.
Types of Curtain Wall Systems
Curtain walls can be premade at the factory and assembled before they are brought into the site. There are mainly two types of curtain wall systems, and they are classified mainly based on the method in which they are assembled.
- Stick Curtain Wall System
- Unitized Curtain Wall System
Stick Curtain Wall System
In the stick curtain wall system, the components will be assembled piece by piece on the construction site itself. This type of system is used in low-rise buildings or smaller regions. This system will provide flexibility as it can give space for onsite adjustment. Even if it has the advantage of low shipping costs, the labour cost and time consumption must not be underestimated, as they tend to be higher.
Unitized Curtain Wall System
In the unitized curtain wall system, the individual parts will be assembled in the factory itself. These components are installed and brought as a single unit from the factory to the site. The size of this type of curtain wall is directly proportional to the floor-to-floor height of the building structure. This can be used in high-rise buildings, as there is no need for any external supports like scaffolding. There will only be a need for a mini crane or temporary hoist to fix these walls into place. The system will provide the advantages of fast construction and uniform quality of components due to the factory manufacturing process. This type of curtain wall has high shipping charges because the size is large and the best protection must be given during the transportation to the site.
Components of a Curtain Wall
The structural elements for a single curtain wall unit installed on a building structure are,
- Transom
- Mullions
- Vision Glass
- Anchor
Transom
Transoms are horizontal bars or beams that connect the vertical members of the curtain walls and provide support for glass and other infill materials. They play an important role in the distribution of loads and help in the overall strength of the curtain wall.
Mullions
Mullions are the vertical components of the curtain wall. They give structural support to the system and also help in the load transfer to the mainframe of the building. These are usually made up of materials like steel or aluminium, and they are designed to be lightweight and durable. They also provide aesthetic function as they can define the appearance of the curtain wall.
Vision Glass
Vision glass represents the transparent or translucent glass panels that are generally used in curtain walls. They allow natural light to fall into the building and improve the energy efficiency. They also provide a visually appealing exterior. Glass panels are normally used for insulation, UV protection, and also durability. The glass can be double or triple glazed and also include low-E coating or reflective coating, depending on the climatic requirements in the area.
Anchor
Anchors are the materials that help the curtain wall system to be attached to the building. This is mainly designed to withstand environmental forces like wind, seismic activity, and thermal expansion and for making sure that the curtain wall remains securely in place.
Advantages of Curtain Walls
- Curtain walls can provide excellent weather protection and improve the performance of the building along with durability.
- They are mainly designed for preventing water, snow, dust and other environmental elements from penetrating the system and helping to keep the interior building dry.
- They are designed for dispersing the stress from sources like high winds and improving the overall steadiness of the building.
- They help in increasing the energy efficiency.
- They can act as a barrier, reduce the spread of the fire, and protect the building from fire.
- They can create a classy appearance for high-rise buildings and low-priced buildings.
- The large glass panels can improve visibility and increase the natural light, making the interior of the building look and feel great.
- They have versatile design options. That is, the curtain wall systems can be designed and manufactured for various ranges of specifications that can suit the specific aesthetics and practical needs of a building.
Disadvantages of Curtain Walls
- Curtain walls can be more expensive for installation and maintenance when compared to other types of building envelopes like masonry or concrete walls.
- Curtain walls may be relatively heavy, and that may need additional support for the structure, which increases the construction cost.
- If it is not properly maintained or installed, curtain walls may leak. This can lead to water damage and other problems in the building.
- Curtain walls may not be able to provide much insulation like other building envelopes; as a result, there may be higher heating and cooling costs.
- Some people may not like the appearance of the curtain wall, as they may think it is cold and impersonal.
- Curtain walls are complex, and they may need special knowledge for installing and maintaining.
- Curtain walls need more frequent maintenance and cleanliness when compared to other types of building envelopes.
Installation Steps for Curtain Walls
- Determination of curtain wall location
- Attaching the mounting angles securely
- Positioning the curtain wall panels
- Sequential installation of panels
- Adjusting the bottom sweep
- Incorporation of doors is optional.
Conclusion
Curtain walls can be considered an advancement in the construction industry which provides a combination of aesthetics, functionality, as well as sustainability. They have the ability to improve the natural light and provide protection from other natural elements like wind. They also help in improving the energy efficiency, and it has become one of the most commonly used parts of the construction of high rise buildings. Choosing a proper curtain wall system will mainly depend on the specific needs of the building.
FAQs
Yes, curtain walls can improve energy efficiency by allowing natural light into the building. However, they may need proper glazing to optimise insulation and energy performance.
Curtain walls are installed by first attaching mounting angles, positioning the panels, and securing them sequentially. Additional adjustments, like adding doors, may be optional.
Yes, curtain walls add weight, but they are designed to be lightweight. Additional support may be required for larger curtain wall systems.
Curtain walls can be more expensive to install compared to traditional walls. The cost includes materials, labour, and additional structural support.
Yes, curtain walls with proper glazing can reduce noise levels. This is particularly beneficial for buildings located in noisy urban environments.