Common Types of Curtain Wall Systems in Modern Building Design
Curtain wall systems are a key component of modern building design, offering a range of benefits such as:
Weatherproofing a structure
Reducing sway in tall buildings
Allowing more natural light to enter
Enhancing thermal efficiency
The most commonly used curtain wall systems include stick-built, unitized, metal or aluminum curtain wall systems, and structural glazing wall systems. Each type is designed to meet specific performance and design criteria, making them integral to contemporary architecture.
The Four Most Common Types of Curtain Wall Systems
Understanding these popular curtain wall systems can help inform decisions based on your project’s requirements and preferences.
1. Stick-Built Curtain Wall Systems
The stick-built curtain wall system involves assembling individual components piece by piece at the job site. This method is ideal for:
Low-rise buildings
Confined areas where exterior access is feasible
Reducing shipping costs
Allowing on-site customization and adjustments
However, it requires additional equipment such as scaffolding and cranes, leading to a substantial investment in time and labor.
2. Unitized Curtain Wall Systems
Unlike stick-built systems, unitized curtain walls consist of prefabricated, pre-assembled, and pre-glazed framing and glass panels. This system is commonly used in high-rise buildings due to benefits such as:
Faster construction and installation
Higher quality control due to off-site fabrication
Reduced on-site labor costs
Minimal on-site equipment requirements
Challenges include the need for temporary hoists or mini cranes during installation and higher shipping costs due to the size and protection requirements of prefabricated units.
3. Metal or Aluminum Curtain Wall Systems
Metal curtain wall systems commonly use aluminum framing, steel, brick, and glass. Some key benefits include:
Greater free spans for architectural flexibility
Increased natural daylight penetration
Fewer vertical and horizontal mullions
The ability to support heavier glass, such as double- or triple-glazed units
Lower long-term maintenance costs
Experts advise against using face-sealed barrier walls, which rely on seals between glass units and frames. Over time, these systems may pose reliability issues.
4. Structural Glazing Wall Systems
Structural glazing wall systems offer versatility in both budget and design while providing aesthetically pleasing results. This system can incorporate:
Monolithic glass
Laminated glass
Dual-glazed units
Triple-glazed insulated glass units (IGUs)
The supporting structure may feature aluminum mullions, glass mullions, steel blades, cables, or stainless-steel rods. Depending on the system, extruded silicone gaskets or wet-sealed silicone may be used for the interior and exterior.
The Advantages of Installing Curtain Wall Systems in Buildings
Curtain wall systems are a popular choice for modern buildings, offering several advantages over traditional construction methods. They create a contemporary appearance while providing excellent energy efficiency and weather resistance. Additionally, different types of curtain wall systems can enhance occupant comfort and reduce cooling and heating costs. Below are some key benefits of curtain wall systems:
Weatherproofing
Curtain walls provide an additional layer of insulation and protect against weather elements, preventing air and water from entering the building.
Reduction in Sway
For taller buildings, curtain walls help withstand high winds by distributing kinetic force across their frame, reducing overall sway. Their wind resistance also provides acoustic insulation and soundproofing.
More Natural Light
Curtain walls allow more natural light into a building’s interior, making spaces feel larger and brighter.
Improved Thermal Efficiency
Glazed glass panels in curtain walls reduce UV light penetration and help stabilize interior temperatures, leading to improved thermal efficiency and lower energy costs.
The Role of Glass in Curtain Walls and Its Impact
Incorporating various glass techniques in curtain walls provides distinct advantages in energy efficiency, sound insulation, structural stability, and aesthetics. Below are some glazing methods and their impacts:
Pressure Plate Glazing
This system installs glass and infill panels from the exterior using dry gaskets. A continuous pressure plate is secured with fasteners, followed by a snap-on mullion cover. While effective, dry gaskets may experience leaks at corners and joints.
Performance improvements include using four-sided gaskets or wet sealants for concealed interior toe beads or exposed interior cap beads.
Interior Dry Glazing
A cost-effective method for installing glass and infill panels from within the building without the need for expensive scaffolding. The frame is fixed with exterior dry gaskets, while a removable stop on the top interior mullion allows easy access.
Installation involves sliding the glass unit into a deep glazing pocket, then shifting it into place—often called “jiggle” or “wiggle” glazing. While this method may slightly reduce performance due to metal-to-metal joints, using wet sealant heel beads can enhance its effectiveness.
Structural Silicone Glazing (SSG)
This method uses a bead of silicone to attach the glass to the frame, with additional weather seals for protection. Four-sided SSG is fully adhered, while two-sided SSG can be combined with pressure plate or wiggle glazing for field installation.
Butt-Glazing
This technique eliminates mullions behind the joint, relying on a sealant, usually silicone, to create a seamless barrier seal.
Glass and Its Impact on Curtain Walls
Glazing plays a crucial role in curtain wall systems, influencing structural integrity, sound control, and energy efficiency.
Structural Integrity
Structural glazing involves large glass panels that provide support, allowing for expansive glass installations with minimal obstructions, maximizing views and natural light.
Sound Control
Varying glass thickness, STC ratings, panes, and materials can significantly reduce outside noise, enhancing indoor comfort.
Energy Efficiency
Curtain wall systems can range from single-skin to triple-skin glazing, optimizing thermal performance. By retaining warmth in winter and repelling heat in summer, they contribute to overall energy efficiency in buildings.
Conclusion
Selecting the right curtain wall system depends on multiple factors, including building height, environmental conditions, design preferences, and budget constraints. Whether you choose a stick-built, unitized, metal, or structural glazing system, each type plays a crucial role in enhancing both the aesthetics and functionality of modern architecture.
