What is Curtain Wall System and Why Do We Use Them?

What is a curtain wall system? Curtain wall systems are non-structural systems for the external walls of buildings. As a global leader in curtain wall system manufacturing, Kawneer engineers a comprehensive range of curtain wall systems available in traditional stick fabrication and unitized options.

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Stick-build curtain wall systems are assembled and glazed in the field with inside or outside glazing options. Unitized curtain wall systems, assembled and glazed in the shop environment, offer the advantage of faster installation, improved product quality and lower installation costs.

Kawneer’s curtain wall systems are engineered to meet the highest standards of performance, design and sustainability. View our Curtain Wall Product Selection Guide

Your next landmark project demands a facade that performs. Today’s architecture must balance bold design with natural light, expansive views, and energy efficiency. That’s where the curtain wall system excels.

A curtain wall is a lightweight, non-load-bearing exterior façade that forms the outer skin of a building. Its strength lies in enabling transparency and scale: framing floor-to-ceiling glass, reducing structural weight, and creating a high-performance building envelope.

At Novum, we’ve helped bring complex designs to life across the globe. We understand the realities you face:

• Architects: How do you bring your vision to life without compromising on form, function, or budget?
• Developers: How do you ensure that eye-catching façade delivers long-term value?
• Construction Managers: How do you manage complex glazing installs on tight timelines?

This guide goes beyond textbook definitions. It’s built from decades of engineering, fabrication, and installation experience on curtain wall projects around the world. We’re here to share what works, so your big ideas become bold, buildable realities.

What is a Curtain Wall System?

A curtain wall system is a non-load-bearing exterior façade that hangs like sophisticated skin from a building’s main structure. It allows you to design a dramatic glass façade without bearing the building’s structural load.

These traits allow for glass curtain wall systems that just weren’t possible before. Here’s what makes them stand out:

• Non-load-bearing—pure aesthetic and performance.
• Reduces structural load, streamlining construction.
• Expansive glazing maximizes daylight and views.
• Protects the building envelope from extreme elements.
• Achieving glass curtain wall systems impossible traditionally.

Key Components of a Curtain Wall System

A curtain wall system might look like a single, seamless surface, but it’s actually a precision-engineered assembly of several essential parts working together. Understanding these components is key to appreciating how these systems achieve their blend of aesthetics and performance.

A curtain wall system includes a sophisticated system of:

• Mullions: The primary vertical framing pieces that run continuously from floor to floor, giving the system its vertical structure.
• Transoms: Horizontal framing pieces that connect the mullions, dividing the facade into individual sections for the glazing or panels.
• Glazing: This is what most people picture – the transparent infill material, almost always glass. It lets light in and offers views out, defining the building’s look.
• Spandrel Panels: Not all parts of a curtain wall are transparent. Spandrel panels are opaque sections designed to hide elements you don’t want visible from the outside, like floor slabs, ceilings, or HVAC systems.
• Anchoring System: Specialized connections that safely transfer wind loads and the curtain wall’s own weight back to the building’s structural frame.
• Gaskets and Sealants: Rubber or silicone strips, and sealants flexible enough to ensure every joint is airtight and watertight, protecting the building envelope from the elements.

Types of Curtain Wall Systems

Choosing a curtain wall system hinges on one big question: how will it be built and installed? The main difference between stick and unitized systems comes down to where they’re put together: on-site or in a factory.

Your choice upfront shapes timelines, budget predictability, on-site quality control, and overall risk for all involved.

Stick Curtain Wall Systems

Stick systems are assembled piece-by-piece directly at the construction site. Vertical mullions are installed first, followed by horizontal transoms, creating the grid. Then, individual glazing units and spandrel panels are set into this framework.

• Pros: They can be more cost-effective for smaller or unusually shaped projects and offer adaptability when dealing with unexpected site conditions. Shipping costs are often lower.
• Cons: Installation is slower because more work happens on-site, leading to greater reliance on field labor quality and more exposure to weather during construction.

Unitized Curtain Wall Systems

On the other side, unitized curtain wall systems involve large, fully assembled modules that are prefabricated in a controlled factory environment. These units arrive on site complete with glazing and infills, ready for rapid installation.

• Pros: You get much higher quality control due to factory assembly. On-site installation is significantly faster, reducing labor costs and minimizing weather delays.
• Cons: These systems typically have a higher initial manufacturing cost and require larger shipping volumes, often needing specialized lifting equipment for placement.

Materials Used in Curtain Wall Construction

When you’re designing or building with a curtain wall system, the materials you choose are just as crucial as the system type. They dictate everything from the facade’s strength and energy performance to its long-term look. So, what exactly goes into making these modern building skins?

The Framework

The skeleton of any curtain wall is its framing system.

• Aluminum: This is the most common choice, and for good reasons. It’s lightweight, naturally resistant to corrosion, and incredibly versatile, easily extruded into complex profiles that allow for intricate curtain wall design.
• Steel: When you need serious strength or larger, unsupported spans, steel steps in. It’s stronger than aluminum and often used for specific structural or aesthetic needs in high-performance designs.
• Wood: Though less common for the primary structure, wood is gaining traction in hybrid systems for its unique aesthetic and sustainable appeal. It brings warmth to facades, often paired with metal for structural integrity.

The Skin

Once the frame is set, the infill materials form the actual cladding that protects and defines the building.

• Glass: Glass is the main material in most curtain wall systems, but the specific type determines the integrity of your project:
  • Tempered glass: This is toughened for enhanced strength and shatters safely into small, dull pieces if broken.
  • Laminated glass: Made from two or more panes bonded by an interlayer, laminated glass offers superior safety (holding fragments if broken), better acoustic performance, and excellent UV protection.
  • Insulated glazing (IGUs): These units feature multiple glass panes separated by sealed air or gas spaces, dramatically improving thermal insulation and boosting overall energy efficiency for the building.
  • High-performance coatings: Beyond the basic types, coatings like Low-E (low-emissivity), solar control, and reflective films are applied to glass to fine-tune thermal efficiency, manage solar heat gain, and control glare.
• Opaque Panels: Not every section of a curtain wall needs to be transparent. Opaque panels, often called spandrel panels, are used to conceal floor slabs, ceilings, or mechanical systems between floors. These can be made from various materials like stone veneer, metal panels, or composite materials, allowing for visual continuity or contrast in the façade.

Performance Factors and Design Considerations

Your curtain wall is non-load-bearing, but it still stands up to immense forces. Think wind load trying to push or pull, the sway of seismic movement, or thermal expansion making materials subtly shift. Meticulous engineering ensures your glass and framing stay stable, protecting the building and occupants, even when nature pushes back.

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This facade is your building’s ultimate climate control—preventing water/air infiltration; it keeps the building envelope truly sealed, protecting interiors from drafts and leaks that plague lesser systems. This directly drives energy efficiency by letting you maximize daylight without heat penalty. Advanced glazing (like IGUs with Low-E coatings) and smart thermal breaks cut heat transfer, slashing energy bills. Plus, intelligent ventilation can even turn your facade into a fresh-air gateway, boosting indoor air quality.

A top-performing curtain wall is also a powerful asset for sustainability, helping your projects achieve certifications like LEED by boosting energy efficiency and supporting smart material choices. But above all, it’s about trust: every system must strictly meet building code regulations. Compliance should always be the goal, so you get the long-term safety and performance your clients expect.

Common Applications of Curtain Wall Systems

You’ll find curtain walls defining the look and feel of:

• Office Buildings: Creating bright, open workspaces and commanding corporate presences.
• High-Rise Residential Towers: Offering residents panoramic views and abundant daylight.
• Airports & Transportation Hubs: Enabling grand, light-filled concourses and impressive entryways.
• Shopping Malls & Retail Centers: Drawing in natural light to enhance the shopping experience and showcase products.
• Institutional & Public Buildings: Like universities, hospitals, and museums, where they create inviting, efficient, and visually impactful spaces.

At Novum Structures, we don’t just supply curtain wall systems—we engineer them for the world’s most ambitious projects. With decades of pioneering work in façade engineering and a portfolio spanning continents, we bring unmatched precision and innovative problem-solving to every challenge.

Take a look at some of our work:

• Olympia West Hall: A prime example of how curtain walls redefine exhibition spaces.

• University of Cincinnati CARE/Crawley Building: Interior: Demonstrates interior applications enhancing complex architectural volumes.

• Coppin State University: Health & Human Services Building Project: Showcasing how curtain walls can balance modern aesthetics with the specific needs of public buildings.

Curtain Wall System FAQs

What is the difference between unitized and stick curtain wall systems?

Stick curtain wall systems are built piece-by-piece on-site, with individual mullions, transoms, and glazing units installed sequentially. Unitized curtain wall systems, conversely, are largely prefabricated into large modules in a factory, then transported to the site for rapid installation.

For a detailed comparison, refer to our Stick vs. Unitized Curtain Wall Systems comparison table above.

Which materials are used in curtain wall construction?

The primary materials used are for framing and infill. Framing is typically aluminum or steel, with occasional use of wood in hybrid systems. Infill materials are predominantly glass (including tempered, laminated glass, and insulated glazing with high-performance coatings for thermal insulation), as well as opaque spandrel panels made from materials like metal, composite, or stone veneer.

How much does a curtain wall system cost per square foot?

Factors influencing the cost include the complexity of the curtain wall design, the specific materials chosen (e.g., type of glass and coatings, framing), the system type (stick vs. unitized), project size, and site-specific installation challenges. It’s best to consult with experts for a project-specific estimate.

Are curtain walls load-bearing?

No, curtain walls are non-load-bearing-they are designed to support only their own weight and the environmental loads acting directly on them (like wind). All these forces are then transferred back to the building’s main structural frame, making them distinct from load-bearing walls.

How do curtain wall systems improve energy efficiency?

Curtain walls are designed to maximize daylighting, significantly reducing the need for artificial lighting. High-performance glazing (such as IGUs with low-E coatings) and integrated thermal breaks in the framing minimize heat transfer, boosting thermal efficiency. Additionally, properly designed and sealed systems prevent air infiltration, further contributing to a tightly controlled building envelope.

Why Architects and Engineers Trust Novum

Architects, engineers, construction managers, and developers turn to Novum Structures because we understand the unique challenges of advanced façade systems. We are more than just a supplier; we are a global innovator and a single-source specialty contractor with decades of hands-on expertise.

What does that mean for your project?

• Integrated Solutions: Unlike fragmented approaches, Novum delivers a complete package—from advanced engineering and precision fabrication in our own ISO-certified factories, to meticulous supply and seamless installation. This full-spectrum control minimizes risk, streamlines communication, and ensures project continuity.
• Design Intent Preserved: Our approach is deeply collaborative. We work closely with you to develop technical solutions that embrace your unique design intent while remaining highly respectful of cost. Our Designer Assist process, for instance, provides immediate feedback during conceptualization, integrating our in-house capabilities to proactively reduce risk and optimize value.
• Unmatched Precision & Quality: Rooted in German engineering principles and with a proven commitment to continuous improvement, we ensure every element of your glazing systems meets the highest standards. We’ve engineered, fabricated, and installed thousands of projects worldwide, from iconic skyscrapers to intricate canopies, proving our ability to execute complex visions with exquisite detail.

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