Complete Guide to Aluminium Curtain Wall Design in the UK

Aluminium curtain walls are widely used in modern construction, providing a sleek, durable, and energy-efficient solution for both commercial and residential buildings. But what exactly are aluminium curtain walls and how do they work? In this guide, we will delve into the world of aluminium curtain walls, exploring their components, benefits, design considerations, types of systems available, and material selection. By the end of this article, you will have a comprehensive understanding of aluminium curtain wall design.

Understanding Aluminium Curtain Walls

Aluminium curtain walls are becoming increasingly popular in modern construction due to their versatility and aesthetic appeal. They are non-structural systems that are attached to a building’s structural frame. They are typically thin and lightweight, providing support for glazing and other cladding materials, such as metal panels or stone veneers, while resisting wind loads and other environmental stresses. Unlike traditional brick or concrete walls, curtain walls allow for greater flexibility in design and can be easily installed and removed. They also provide natural light and views while reducing energy consumption and costs.

Components of Aluminium Curtain Walls

Aluminium curtain walls consist of several components, each of which plays an important role in the overall functionality and performance of the system. These components include:

• Frame: The frame is the outermost part of the curtain wall system and is supported by structural elements of the building. It is typically made of aluminium extrusions that are connected together to form a grid-like structure.
• Mullion: Mullions are vertical members that connect the frame to the building, providing additional support and stability. They are typically placed at regular intervals along the length of the curtain wall.
• Transom: Transoms are horizontal members that run across the frame, providing additional support and stability. They are typically placed at regular intervals along the height of the curtain wall.
• Glazing: Glazing is the glass or other transparent material that fills the space between the frame and acts as a thermal barrier. It can be single or double glazed, and may include features such as low-e coatings or tinted glass to improve energy efficiency.
• Insulation: Insulation is used to improve thermal performance, reducing heat loss and improving energy efficiency. It is typically placed between the glazing and the frame.
• Backpan: A backpan is installed behind the glazing to prevent water intrusion and provide additional support. It is typically made of aluminium or other non-corrosive materials.
• Fasteners: Fasteners are used to connect the curtains to the frame and the building structure. They are typically made of stainless steel or other non-corrosive materials to prevent rust and corrosion.

Benefits of Using Aluminium in Curtain Walls

Aluminium has several advantages over other materials used in curtain walls, including:

• Lightweight and strong: Aluminium has a high strength-to-weight ratio, making it ideal for use in curtain walls. It is lighter than steel, yet still provides excellent structural support.
• Flexible: Aluminium can be easily shaped and formed into various sizes and shapes, allowing for greater design flexibility. It can also be anodized or painted to match any desired color scheme.
• Durable: Aluminium is corrosion-resistant and does not rust, making it ideal for use in harsh environments. It is also resistant to UV rays and other environmental factors that can cause damage over time.
• Easy to maintain: Aluminium is low maintenance and easy to clean. It does not require painting or other treatments to maintain its appearance, and can be easily cleaned with soap and water.
• Energy-efficient: Aluminium is a good conductor of heat, making it energy-efficient and cost-effective. It can help reduce energy costs by keeping buildings cooler in the summer and warmer in the winter.

Overall, aluminium curtain walls are an excellent choice for modern construction projects. They offer a range of benefits, including improved energy efficiency, greater design flexibility, and low maintenance requirements. If you are considering a curtain wall system for your next project, be sure to explore the many advantages of using aluminium.

Design Considerations for Aluminium Curtain Walls

Designing aluminium curtain walls requires careful consideration of several factors, including:

Structural Requirements

Curtain walls must be designed to withstand wind loads, seismic loads, and other environmental stresses. The structural engineer must factor in the weight of the glazing, insulation, and other materials used in the curtain wall system to ensure that it is strong enough to withstand these loads.

One important consideration is the height of the building. Taller buildings require curtain walls that can withstand greater wind loads. The curtain wall system must also be able to withstand seismic activity, which can be a significant concern in some areas.

Thermal Performance

Curtain walls can contribute significantly to a building’s energy performance. They can either help to keep the heat inside the building by reducing heat loss or keep the heat outside during the summer by blocking solar gain. Designers must consider the thermal properties of each component and the entire system to achieve optimal performance.

One way to improve the thermal performance of a curtain wall system is to use double or triple glazing. This can significantly reduce heat loss and improve energy efficiency. Another consideration is the use of insulation, which can help to reduce thermal bridging and improve the overall performance of the system.

Acoustic Performance

Curtain walls can also affect a building’s acoustic performance, providing a barrier against external noise. Designers must consider the types of glass and glazing used and any additional insulation that may be required.

Acoustic laminated glass can be used to reduce noise levels, as can the use of thicker glass. Insulation can also be added to the curtain wall system to further improve acoustic performance.

Aesthetic Considerations

The appearance of aluminium curtain walls can be highly customized to suit the building owner’s preferences. Designers can choose from various finishes, colors, and textures to create a unique and appealing appearance.

Some popular finishes for aluminium curtain walls include anodized finishes, which provide a durable and long-lasting finish, and powder-coated finishes, which offer a wide range of color options. Textured finishes, such as wood grain or stone finishes, can also be used to create a unique look.

Fire Resistance and Safety

Curtain walls must also meet fire resistance requirements to ensure the safety of building occupants. Fire-resistant glass and insulation can be incorporated into the system to limit the spread of fire.

Other safety considerations include the use of laminated glass, which can help to prevent injuries in the event of breakage, and the use of safety harnesses and other safety equipment during installation and maintenance.

Types of Aluminium Curtain Wall Systems

There are several types of aluminium curtain wall systems, including:

Stick Systems

Stick systems are the most traditional type of curtain wall system, consisting of individually assembled components that are brought to the building site and installed piece by piece. They are highly customizable and can be used on buildings of any height or size.

Unitized Systems

Unitized systems involve the assembly of curtain wall components off-site into large sections, or units, that are then transported to the building site and installed as a pre-fabricated unit. They can save time and labor costs, especially for larger buildings, and provide better quality control.

Semi-Unitized Systems

Semi-unitized systems combine the benefits of stick and unitized systems, featuring pre-assembled units that are joined together on site with extruded metal framing.

Structural Glazing Systems

Structural glazing systems rely on the use of silicone adhesives instead of metal framing to hold the glass in place. This creates a seamless appearance, and a greater glass area is visible than in other systems.

Material Selection for Aluminium Curtain Walls

Choosing the right materials for aluminium curtain walls is crucial to achieving optimal performance. Considerations include:

Aluminium Alloys and Their Properties

Various types of aluminium alloys are available for use in curtain walls, including 6061, 6063, and 3004. Each has different properties, such as strength, ductility, and corrosion resistance, that must be taken into account when selecting the right alloy.

Surface Treatments and Finishes

Aluminium curtain walls can be finished with various treatments and coatings, such as anodizing, powder coating, and fluoropolymer resins. These finishes improve the curtain wall’s durability, corrosion resistance, and appearance.

Glass and Glazing Options

The types of glass and glazing used in curtain walls can significantly impact the building’s performance. Different types of glass, such as low-E or insulated, can help to reduce energy consumption and increase thermal efficiency. Glazing options, such as spandrel glass or photovoltaic glass, can also provide additional functionality or aesthetic appeal.

Conclusion

Aluminium curtain walls are an essential element of modern construction, combining energy efficiency, durability, and aesthetics. Designing and constructing aluminium curtain walls requires careful consideration of several factors, including structural requirements, thermal and acoustic performance, aesthetic considerations, and material selection. By understanding these factors, designers can create curtain walls that are both effective and appealing in appearance.