Parts and Components of Curtain Walls

September 9, 2023
Posted in Curtain Wall
September 9, 2023 admin

In modern architecture, the interplay of form and function has given rise to innovative building designs that captivate the eye and redefine the boundaries of structural engineering. Among these architectural marvels, curtain walls stand tall, quite literally, as a symbol of contemporary aesthetics and sustainable construction. These towering facades, which grace the skylines of cities around the globe, are more than just a decorative shell; they represent the fusion of artistry and engineering precision. To truly appreciate the beauty of curtain walls, one must delve into their intricate anatomy. In this exploration, we will dissect the various parts and components of curtain walls, unraveling the secrets behind their visual allure, energy efficiency, and structural integrity. Join us on this journey through the intricate world of curtain walls, where glass, metal, and ingenuity converge to redefine the modern urban landscape.

Characteristics of Curtain Walls

characteristics of curtain walls

Curtain walls are a distinctive architectural feature known for their unique characteristics that set them apart from traditional building facades. Before getting to the components of curtain walls, let’s first talk about the characteristics of these cladding materials.

These characteristics include:

1. Transparency: The most defining characteristic of curtain walls is their transparency. They predominantly comprise glass or other transparent or translucent materials, allowing natural light to flood interior spaces. This transparency creates a connection between the indoor and outdoor environments and provides unobstructed views of the surroundings.

2. Non-Structural: Curtain walls are non-structural elements, meaning they do not bear the weight of the building. Instead, they hang like a curtain from the building’s structural frame. This allows for greater design flexibility and the incorporation of larger expanses of glass.

3. Aesthetic Appeal: Curtain walls are often chosen for their aesthetic appeal. They allow architects and designers to create visually striking, modern, and iconic building exteriors. Curtain walls’ sleek, minimalist look can make a bold architectural statement.

4. Weather Resistance: Curtain walls are designed to withstand various weather conditions, including wind, rain, snow, and temperature fluctuations. They act as a protective barrier, keeping the interior of the building comfortable and dry.

5. Energy Efficiency: Modern curtain walls incorporate energy-efficient features, such as thermal insulation and low-emissivity coatings on glass, to improve the building’s energy performance. These elements help reduce heating and cooling costs and minimize the structure’s carbon footprint.

6. Structural Integrity: While curtain walls are non-structural, they must still possess structural integrity. They are engineered to withstand wind loads, seismic forces, and other external pressures without compromising stability.

7. Customization: Curtain walls can be customized to fit the specific architectural and functional requirements of a building. They come in various shapes, sizes, and configurations, allowing architects to create unique and innovative designs.

8. Modularity: Curtain walls are typically assembled from standardized, modular components. This modularity streamlines the construction process and makes replacing damaged or worn-out parts easier without affecting the entire wall system.

9. Maintenance and Accessibility: Curtain walls may require specialized maintenance due to their height and often complex design. Access systems like window-washing equipment or maintenance walkways are often integrated into the design to ensure that the exterior can be adequately cleaned and maintained.

10. Integration of Technology: Modern curtain walls can integrate advanced technologies, such as automated shading systems, embedded sensors, and even solar panels. These features enhance the overall functionality and sustainability of the building.

11. Sustainable Design: Many contemporary curtain walls are designed sustainably. They can incorporate features like green roofs, rainwater harvesting, and daylight harvesting to reduce the environmental impact of the building.

Learn about types of curtain wall systems.

What are the Parts and Components of Curtain Walls?

components of curtain wallsMullions:

Mullions are vertical or horizontal structural components of curtain walls. Vertical mullions run vertically between floors, while horizontal ones, known as transoms, run horizontally between mullions. These components provide stability to the curtain wall, distribute loads, and serve as the primary framing elements. Mullions can be made of materials like aluminum, steel, or even glass, and they play a critical role in the structural integrity and aesthetics of the curtain wall.


Transoms are horizontal structural members that connect mullions in multi-story curtain walls. They help distribute the load evenly across the curtain wall, ensuring stability and integrity. Transoms are essential for supporting the weight of the glass panels or other infill materials used in the system.

Glass Panels:

Glass panels are the most visible and distinctive components of curtain walls. They provide transparency and allow natural light into the building. Glass panels can vary in thickness type (clear, tinted, reflective, etc.) and may include insulation or sun control coatings. The choice of glass can significantly impact the curtain wall’s aesthetics and energy efficiency.

Spandrel Panels:

Spandrel panels are opaque or non-vision glass panels that cover the floor slabs or structural elements behind the curtain wall. They maintain the visual continuity of the façade and can be coordinated with the overall design theme. Spandrel panels are often chosen for their aesthetic properties and can come in various colors and finishes.

Pressure Plates and Caps:

Pressure plates and caps are parts of curtain walls that secure the glass or infill panels within the cladding framing system. Pressure plates apply pressure to the edges of the glass, holding it in place, while caps cover and protect the exposed edges, enhancing the appearance and weatherproofing of the curtain wall.

Gaskets and Sealants:

Gaskets and sealants are essential components of curtain walls that are used for creating an airtight and watertight seal in the cladding system. Rubber gaskets and specialized sealants are applied between the glass or panels and the framing members to prevent air and water infiltration, ensuring the curtain wall’s performance and durability.

Thermal Breaks:

Thermal breaks are insulating materials typically made of plastic or rubber. They are incorporated into the framing system to reduce thermal conductivity and prevent heat transfer through the frame. This feature helps improve the curtain wall’s energy efficiency and thermal performance.


Additional insulation materials can be added within the curtain wall system to enhance energy efficiency and thermal performance. Insulation helps maintain a comfortable indoor environment by reducing heat transfer through the curtain wall.

Sunshades and Louvers:

Sunshades and louvers are optional components of curtain walls integrated into cladding systems to provide shading and control the amount of direct sunlight entering the building. They enhance occupant comfort, reduce glare, and contribute to energy efficiency.

Fasteners and Anchors:

Fasteners and anchors are hardware components of curtain walls used to securely attach the cladding panels to the building’s structural frame. These elements are crucial for maintaining the stability and safety of the curtain wall system.

Silicone and Sealant Joints:

Silicone and sealant joints are applied to fill gaps between glass panels, mullions, transoms, and other components. They create an effective seal that prevents water infiltration and ensures the curtain wall’s weather resistance and structural integrity.

Substructure Components of Curtain Walls:

The substructure refers to the building’s underlying structural system, including columns and beams made of materials like steel or concrete. The curtain wall is anchored to this substructure to provide support and stability.

Supporting Frame:

The supporting frame holds mullions, transoms, and other components in place. It is typically constructed from materials such as aluminum or steel. This frame plays a central role in the structural integrity of the curtain wall.

Anchorage and Attachment Systems:

Anchorage and attachment systems include various hardware and methods used to securely connect the curtain wall to the building’s structural frame. These systems are essential for ensuring the curtain wall’s stability and safety.

Infill Panels:

Infill panels are other components of curtain walls that are non-glass or non-transparent panels, often made of materials like metal, stone, or composite materials. They complement the glass panels, adding aesthetic diversity and functionality to the curtain wall.

Drainage System:

The drainage system is also a component of curtain walls consisting of weep holes and channels designed to allow water to drain away from the curtain wall. This system prevents water buildup, moisture infiltration, and potential leaks.


Accessories, such as cover caps, end caps, and trim pieces, provide finishing touches to the curtain wall system. They are used for both aesthetic and functional purposes, enhancing the overall appearance and performance of the curtain wall.