Curtain Wall Systems and Why You Need Them

Curtain walls are a popular type of glazed wall system that are used widely on commercial projects across Australia. Read on to find out what curtain walls are and whether they’re the right choice for your project.

What is a curtain wall?

A curtain wall is a type of non-structural wall system that covers the exterior of a building to keep weather out and protect occupants within the building. 

Curtain walls are not structural which means they do not hold any weight or load of the building except their own weight. Any wind pressures that are applied to the surface of a curtain wall are transferred to the main structure of the building.

Curtain walls are typically made from glass panels with steel or aluminium frames called mullions. Glass curtain walls can give a building the impressive appearance of being made from glass top to bottom. Sometimes the panels may be made from metal sheets or thin stone instead of glass.

What is the purpose of a curtain wall?

The purpose of a curtain wall is to keep weather, such as wind, rain and extreme temperatures, out of a building and to protect the occupants and objects inside the building. 

By resisting weather elements, curtain walls also help protect the building materials and increase the longevity of the building structure itself. Curtain walls are designed to reduce building sway by effectively distributing any wind load applied to the exterior.

What are the types of curtain walls?

Curtain walls are classified as either stick systems or unitised systems (also known as modular systems). 

Stick Systems 

Stick systems are installed as long pieces known as sticks. The sticks are put in place on the exterior of the building structure piece by piece. This allows for adjustments to be made on site as appropriate. Stick systems are typically used on low to mid rise building projects.

Unitised Systems

Unitised systems are installed as large units which are fabricated and joined together in the factory prior to being delivered to the worksite. This helps save on installation time and costs. Unitised systems are more commonly used in high rise buildings.

What is the difference between a window wall and a curtain wall?

Window walls and curtain walls are two of the most commonly used glass wall systems in modern construction.

The main difference between the two systems is that the window wall is placed structurally between the concrete slabs of a building whereas the curtain wall is hung off or attached to the outside of the concrete slabs.

Window walls are easier to install and less expensive than curtain walls. They are most commonly used in residential buildings where balconies and operable windows are required. 

Curtain walls are able to achieve a higher level of aesthetic appeal because of the amount of glass used. Installing curtain walls requires access to the exterior of the building using a crane or rig, which makes it more expensive. Curtain walls are most commonly used in commercial projects and high rise buildings.

What is the difference between a storefront and a curtain wall?

Like curtain walls, window storefront walls are non structural wall systems. Storefronts are typically used on the ground floor of a building as a commercial entrance. They are thinner than curtain walls and usually have a height restriction.

Storefronts cost less and are faster to install than curtain walls but they are far less versatile. Curtain walls offer better weather protection and durability and can be extended over multiple floors.

What are the advantages of curtain wall systems?

There are several reasons why curtain wall systems are a popular choice for modern building projects. The advantages include:

Superior weather protection

Curtain walls are designed to prevent moisture and air from getting inside a building. Curtain walls that have been pressure equalised are particularly effective at weather protection. In these systems, the face of the glass and the glazing act as a rain screen, while an air barrier inside the system helps equalise the pressure to prevent water from penetrating.

Thermal performance

Curtain walls use glass that has been treated and glazed for improved thermal performance. That means less heat escapes during winter and less heat is gained during summer, improving the overall energy efficiency of the building.

Fire resistance

Curtain wall systems can help slow down the spread of fire in case of an emergency by acting as a barrier and compartmentalising the building. The glass in curtain wall systems is treated to meet certain fire safety requirements. It can also be treated to improve security from burglaries and ballistics if required.

Versatility and design

Curtain walls allow for flexible and versatile designs which architects and builders can use to their advantage. Curtain walls can achieve a wide range of practical and aesthetic requirements.

Aesthetics and visibility

Curtain walls are often used to create a sleek, classy and sophisticated appearance for commercial buildings. The use of glass can improve natural lighting inside the building to create an open and spacious feel.

What are the disadvantages of curtain wall systems?

The main disadvantages of curtain wall systems is that they tend to have higher costs and are more labour intensive than other systems, such as window walls. 

However, curtain walls do offer a number of performance, safety and appearance advantages, which may be worth the cost. Each project is different and individual project needs should be considered when deciding if curtain walls are the right choice.