Curtain walling is the main system that holds unbroken sheets of glass in place.
The term describes a light, non-load-bearing facade system fitted to the outside of a building. It separates the interior from the external environment, but unlike a traditional masonry wall, it doesn’t carry the weight of the floors or roof.
Although commonly associated with glass-fronted offices and high-rise developments, curtain walling doesn’t have to be entirely glazed. Often, these systems combine an aluminium frame with vision glass, opaque or spandrel panels and metal panels.
The structure creates an envelope that protects the property, but still gives architects considerable design freedom. So, what is curtain walling? It’s the first line of defence against the elements.
How does a curtain wall system work?
To understand how a curtain wall system works, you first need to differentiate it from normal construction methods. In a concrete building, the exterior walls are load-bearing, meaning they’re responsible for holding up the roof and the floors above them.
But, as we mentioned earlier, a curtain wall is entirely non-load-bearing. The only weight it supports is its own, along with the environmental forces acting directly upon it (e.g., high winds, rain, earthquakes).
So, instead of holding the building up, the curtain wall transfers these external forces back to the primary building structure through precisely engineered connection points.
The system is typically constructed from lightweight extruded aluminium frames (which act as the skeleton). The aluminium grid can be filled with glass panels to create a transparent envelope, or fitted with solid metal panels, stone veneers, or louvres for ventilation.
What are the benefits of a curtain walling system?
The performance of curtain walling depends on its specification and installation, but the principal benefits include:
1. Maximising natural light
A glass-dominated facade allows a massive amount of natural light into a building.
Particularly if a building has a dark, enclosed interior, curtain walling can make a massive improvement. From a commercial perspective, glass curtain walling can even reduce the reliance on artificial lighting, lowering electricity costs.
More importantly, it creates a much nicer environment for tenants and employees. Plenty of studies have shown that exposure to natural light in the workplace leads to higher overall productivity.
2. Weather protection
Without curtain walling, a building would be vulnerable to water infiltration and air leaks. As part of the building’s protective external envelope, these systems are engineered to create airtight and watertight seals.
Some curtain walls incorporate thermal breaks: materials within the aluminium frame that interrupt the conductive path.
These materials prevent the cold from transferring inside during the winter and keep the heat out in summer – this then has a direct impact on the building energy-efficieny.
When it requires less mechanical heating and cooling, it translates to lower utility bills.
3. Long lifespan
Did you know that a well-maintained curtain walling system can last for three to five decades?
With the right specification and planned maintenance, a curtain wall system can remain in service for many years. Aluminium, the primary material in today’s curtain walling systems, is highly resistant to rust and corrosion.
Combined with high-quality glazing and weather-resistant sealants, the final facade can withstand exposure to harsh environmental conditions with very minimal degradation.
Stick vs unitised: which system do you need?
If you’re currently specifying a curtain wall for a project, there are two main installation methods to choose from (and which you choose will depend entirely on the scale, location, and specific logistical requirements of the build).
1. Stick system
In a stick system, the curtain wall is built piece by piece directly on the construction site. The vertical aluminium mullions are installed first, followed by the horizontal transoms, and as the final step, the glass or infill panels are fitted into the grid.
As it is assembled on-site, a stick system offers a lot of flexibility – it’s often the ideal solution for existing tenanted buildings, complex low-rise structures, or projects where the facade needs to be retrofitted around current architectural features.
2. Unitised system
Unitised systems consist of large, fully assembled panels that are manufactured off-site in a controlled factory environment. These complete units (the frame, glass, and seals) are then transported to the site and lifted into place using cranes.
The bulk of the assembly is done beforehand, which means on-site installation is incredibly fast. For large-scale new builds, where installation speed is critical, unitised systems are often the go-to choice.
Why choose Pops Facades for your building envelope?
The performance of a curtain wall depends not only on the system specified, but also on the quality of its installation.
Your team needs to plan logistics, access, lifting, setting out and interfaces with the wider building envelope. At Pops Facades, we provide comprehensive solutions for your entire building envelope.
Established in 2007, we can support building managers by addressing a single damaged glass panel or managing the installation of a full-building envelope.
