What Is Curtain Walling – Everything You Should Know

Curtain walling is a lightweight, non-load-bearing external façade system used to enclose commercial buildings. It typically combines aluminium framing with glass panels to protect the building from weather while allowing natural light into the interior.

Unlike a structural wall, curtain walling does not support the building’s floors or roof. Instead, it is fixed to the building’s structural frame and transfers its own weight and environmental loads back to that structure.

It is widely used on offices, commercial developments, retail buildings, hotels and other large-scale projects where daylight, weather protection and façade design need to work together.

How Does Curtain Walling Work?

Curtain walling is attached to the structural frame of a building rather than forming part of the primary structure.

A typical system consists of:

• Mullions: Vertical aluminium framing members that provide the main support.
• Transoms: Horizontal members that divide and support the façade panels.
• Glass panels: Usually insulated glazing units selected according to thermal, solar and acoustic requirements.
• Gaskets and seals: Help provide weather and air resistance.
• Fixings and brackets: Connect the curtain wall system to the building structure.

The system is engineered to withstand loads such as wind pressure while allowing controlled movement caused by factors such as thermal expansion and building movement.

For a closer look at how commercial glass curtain walling works, see our guide to glass curtain walling.

What are the Main Types of Curtain Walling?

Curtain walling is generally divided into two main installation approaches.

1. Stick Curtain Walling

Stick systems are assembled on site, with individual mullions, transoms and glazing components installed progressively. They can be useful when:

• The building has a complex design.
• Site access is straightforward.
• Flexibility during installation is important.
• The project requires adjustments on site.

2. Unitised Curtain Walling

Unitised systems are manufactured and glazed into large panels before being delivered to site. They can be advantageous for:

• Large commercial developments.
• High-rise buildings.
• Projects requiring faster installation.
• Controlled factory production.

The appropriate system depends on the building design, project programme, access and installation requirements.

What is Curtain Walling Made From?

Modern curtain walling commonly combines aluminium framing with glass, although other infill materials can also be incorporated depending on the façade design.

Key components can include:

Glass specification can be tailored according to the project’s requirements, including thermal performance, solar control, acoustic performance and safety.

Where is Curtain Walling Used?

Curtain walling is particularly suited to commercial buildings with large external elevations. Common applications include:

• Office buildings.
• Business parks.
• Retail developments.
• Hotels.
• Educational buildings.
• Healthcare facilities.
• Mixed-use commercial developments
• High-rise buildings.

It is often used where large areas of glazing are required without making the façade part of the building’s load-bearing structure.

What are the Benefits of Curtain Walling?

The main benefits of curtain walling include:

• More Natural Daylight: Large glazed areas allow daylight to penetrate deeper into commercial interiors, potentially reducing reliance on artificial lighting during daylight hours.
• Weather Protection: A properly designed curtain wall system helps protect the building interior from wind, rain and other external conditions.
• Thermal Performance: Curtain walling can incorporate insulated glazing and thermally improved framing to help control heat loss and solar gain.
• Design Flexibility: Commercial façades can be configured with different glass specifications, frame finishes, panel arrangements, opening elements, spandrel sections.
• Efficient Use of External Space: Because curtain walling is attached to the structural frame, it provides a relatively lightweight method of enclosing large building elevations.

Is Curtain Walling Structural?

No. Curtain walling is non-load-bearing. Its purpose is to form the building envelope rather than support structural elements such as floors, beams or the roof.

However, the system still needs to be engineered to withstand loads imposed on the façade, particularly wind loads and its own weight.

This distinction is important when comparing curtain walling with other façade systems.

Curtain Walling vs Structural Glazing: What’s the Difference?

The main difference is how the glass is supported and presented externally.

Curtain walling uses a visible aluminium frame to support the glazing, while structural glazing uses specialist bonding to create a façade with minimal visible external framing.

Read More: Curtain Wall vs. Structural Glazing

Is Curtain Walling Suitable for Commercial Offices?

Yes. Curtain walling is widely used for office buildings because it can combine large glazed areas with thermal, acoustic and weather-performance requirements.

For an office project, the specification should consider:

• Building orientation.
• Solar exposure.
• Glazing performance.
• Thermal requirements.
• Acoustic requirements.
• Ventilation strategy.
• Maintenance access.
• Building height and wind exposure.

The right specification is therefore about more than choosing a frame and glass appearance.

What Should You Consider Before Choosing Curtain Walling?

Before specifying a curtain wall system, consider the following:

• Building performance: Determine the required thermal, acoustic, solar and weather performance.
• Glass specification: The type and configuration of glass can have a significant effect on comfort and energy performance.
• Building design: The façade should work with the structural grid, floor levels and architectural design.
• Maintenance: Consider how glazing, seals and other components will be inspected, cleaned and replaced.
• Installation method: Stick and unitised systems have different installation requirements and may suit different project programmes.
• Budget and lifecycle costs: Look beyond the initial installation price and consider maintenance and replacement requirements over the building’s lifespan.

What Does Curtain Walling Cost?

There is no single cost for curtain walling because pricing depends on the specification and complexity of each project. Factors that can affect the overall cost include:

• Total façade area.
• Glass specification.
• Frame system.
• Building height.
• Project complexity.
• Installation method.
• Thermal and acoustic requirements.
• Access and site conditions.
• Bespoke design requirements.

For commercial projects, obtaining a project-specific quotation is more useful than relying on a generic cost-per-square-metre figure.

Final Thoughts

Curtain walling is a non-load-bearing façade system designed to enclose commercial buildings while providing weather protection, daylight and architectural flexibility.

Its aluminium framing and glazed panels can be specified to meet different thermal, acoustic, solar and design requirements.

For commercial projects, the most suitable curtain walling system depends on the building’s design, performance requirements, installation conditions and long-term maintenance needs. Considering these factors early can help ensure the façade performs effectively throughout the building’s lifecycle.