Similar to commercial glass curtain walls, residential curtain wall systems encompass buildings with non-structural glass and aluminum facades that bear loads and provide resistance to the building’s primary structure. These glazing systems incorporate thermally broken, robust glass panels to enhance heat efficiency. The mullions, transoms, and sealings offer additional functional and structural advantages, including protection against:
- Wind: The curtain wall system is designed to withstand the forces exerted by strong winds and prevent air and water infiltration.
- Water: The sealings and proper system installation ensure water does not penetrate the building, preventing leaks and water damage.
- Thermal: The thermally broken heavy-duty glass panes help to minimize heat transfer, improving the building’s energy efficiency and reducing heating and cooling costs.
- Structural Instability: The mullions and transoms contribute to the overall stability of the curtain wall system, enhancing the structural integrity of the building.
- Seismic: The curtain wall system is engineered to withstand seismic forces, reducing the risk of damage during earthquakes.
- Impact: The glass used in the system may have enhanced impact resistance, reducing the likelihood of breakage due to external forces.
- Fire: Depending on the materials used, the curtain wall system can offer varying fire resistance, contributing to the building’s overall fire safety.
- Sound: The glass and sealings can help reduce noise transmission from the outside, improving acoustic comfort inside the building.
Modern residential curtain wall systems, with their state-of-the-art glass shells, serve as a protective barrier against external elements, ensuring a safe and comfortable living environment while providing optimal thermal performance for the occupants. These advanced glazing solutions are also prominently utilized in commercial applications.
The practical combination of glass and aluminum in constructing contemporary curtain wall systems plays a defining role in modern residential architecture.
Installation of Residential Curtain Wall Windows
You can retrofit your home using various residential curtain wall systems and glass partition walls if you consider your load-bearing walls.
It’s crucial to understand that glass curtain walls are non-load-bearing. Consequently, replacing any wall with a glass and aluminum structure requires careful consideration of its structural implications.
However, the installation process becomes straightforward and uncomplicated if a wall is non-load bearing.
The foundation of all glass curtain wall systems lies in lightweight and durable aluminum framing. Accurate measurements are of utmost importance before the components are cut to the required size by the manufacturer. Upon arrival of the components on-site, an installer meticulously double-checks the measurements to ensure the perfect fit of each frame.
Once the frame is securely in place, the glass panels are carefully installed, and the installer verifies the fitment again, completing the installation process.
Glass residential curtain wall systems typically necessitate custom specifications and fitting for almost every instance. There is no universal, off-the-shelf solution, as each project is distinct and requires tailored design and implementation.
Learn about window wall and curtain wall differences.
Duration of Residential Curtain Wall Systems Installation
The manufacturing process is the most time-consuming aspect to consider when estimating the lead time for installation. It is the primary factor influencing the time between placing an order and completing the installation. Depending on the precision of on-site measurements, this lead time can range from 4 to 10 weeks.
Additionally, factors such as the size and complexity of the project introduce further variables for glass curtain wall manufacturers, potentially extending the lead time required.
By implementing effective planning and preparation, it is possible to reduce lead times by half. A skilled project manager ensures a swift and efficient installation process.
Types of Residential Curtain Wall Systems
Three available systems for residential curtain wall installations are face-sealed, water-managed, and pressure-equalized.
Among these, pressure-equalized residential curtain wall systems provide the highest air and water infiltration resistance, while water-managed systems offer the next level of reliability.
Pressure-equalized curtain wall systems create an airtight barrier on the inside faces of glass and glazing pockets, with the outside faces serving as a protective layer to shed water away.
A pressure-equalization chamber in the glazing pocket reduces water penetration by equalizing pressure differences. Minor water infiltration is harmlessly wept to the exterior.
Water-managed systems have drains and weeps in the glazing pocket but lack an air barrier or zone-glazing of each glass unit, resulting in more water entering the system and requiring drainage. Leaks can occur if the pressure differential forces water above interior gaskets.
Face-sealed barrier walls, still found in some residential curtain wall systems, rely on perfect seals between glass units and frame members. These systems are less reliable in the long term and should be avoided.
Learn more about different types of curtain wall systems.
Residential Curtain Wall Cost
The cost of a glass curtain wall typically ranges from $25 to $140+ per square foot, depending on various factors such as the type of glass, level of transparency, design complexity, thickness, and the chosen company for the installation. Several aspects can influence the installation cost, including the type, size, treatment, and availability of the glass, design intricacy, modifications, performance evaluation scope, manufacturing complexity, special elements, approval process, and logistics.
For instance, replacement projects may cost between $175 to $250 per square foot, while initial installations can range from $25 to $75 per square foot. It’s worth noting that these price ranges apply to both residential and commercial applications.
Thermal Performance of Residential Glass Curtain Walls
The overall thermal performance of residential curtain wall systems depends on several factors, including the glazing infill panel, frame material, construction behind opaque areas, and perimeter details.
Residential curtain wall frames often incorporate thermal breaks made of low-conductivity materials, like PVC, Neoprene rubber, polyurethane, or polyester-reinforced nylon, to improve thermal performance.
These breaks minimize heat transfer and condensation issues. Some systems use pressure bars with gaskets acting as thermal breaks and aiding acoustic isolation.
Proper design and construction are crucial to maintaining the continuity and effectiveness of these elements.
For the opaque areas of the residential curtain wall, insulation and air/vapour barriers play a key role in controlling temperature and humidity fluctuations. Careful detailing of these elements minimizes condensation risks. Drainage provisions, like condensate gutters, may be included, but they must not violate the air barrier unless placed outboard of the backplane.
Ensuring continuity of the air barrier around the residential curtain wall perimeter reduces airflows and integrates with perimeter flashings for watertight performance. Proper insulation placement reduces energy loss and potential condensation. It’s important not to insulate between the interior portion of mullions and adjacent wall construction to prevent condensation issues in the spandrel area.
Moisture Protection Performance of Residential Curtain Walls
Water penetration resistance in the exterior wall system is impacted by multiple factors, such as glazing details, frame construction, drainage details, weatherstripping, frame gaskets, interior sealants, and perimeter flashings and seals.
Water infiltration can happen as a result of five forces: gravity, kinetic energy, air pressure difference, surface tension, and capillary action. To prevent water infiltration, the system design must effectively address these forces.
Unlike smaller discontinuous windows, which can use sill flashings to manage frame corner leakage, curtain walls cover large wall expanses and lack sill flashings at each glazed opening. As a result, curtain walls demand special attention in their design and construction.
Properly constructing watertight frame corners and effective glazing pocket drainage is crucial for ensuring reliable water penetration resistance, as any leaks in curtain wall frame corners can lead to the interior or lower-level glass damage.
Residential Curtain Wall Designs (Style and Aesthetics)
Residential curtain walls exhibit two primary visual characteristics: glazing appearance and sightlines. Sightlines refer to the visual profile formed by the vertical and horizontal mullions within the curtain wall system. The sightlines are determined by both the width and depth of the curtain wall frame.
The lateral load resistance requirements, such as wind loads and spans, typically influence the depth of the frame. In situations where narrow sightlines are preferred for aesthetic reasons, steel stiffeners can be inserted into the hollow frame of aluminum extrusions to reduce the frame depth effectively.
Achieving a slender and minimalist look is often desirable for modern architectural designs, and narrow sightlines play a significant role in achieving this aesthetic. By using steel stiffeners in the frame, designers can maintain structural integrity and meet load resistance requirements while achieving the desired slim sightlines that enhance the overall appearance of the curtain wall. This method offers flexibility in design without compromising the performance and stability of the system. As a result, the visual impact of the curtain wall is enhanced, creating an elegant and sophisticated look for the building’s exterior.
Sound Insulation of Residential Curtain Wall Systems
The glazing and internal seals mainly influence the acoustic performance of curtain walls to prevent air leakage, as discussed elsewhere.
Specific measures can be taken to enhance the sound attenuation capabilities of curtain walls. Installing sound attenuating infill and ensuring airtight construction are effective ways to improve acoustic performance.
Another way to mitigate exterior noise is by incorporating insulated glass units with varying thicknesses. Increasing the thickness of one of the glass panes or using a laminated layer of glass with a noise-reducing interlayer, such as polyvinyl butyral (PVB), can help to reduce sound transmission.
By implementing these strategies, curtain walls can be optimized for better acoustic insulation, creating a more peaceful and comfortable indoor environment shielded from external noises.
Back Pans and Shadow Boxes
Back Pans for Residential Curtain Walls
Back pans, commonly crafted from aluminum or galvanized steel, are securely attached and sealed to the curtain wall framing around the perimeter. They are positioned behind the opaque sections of the curtain wall to provide additional support and protection.
In colder climates, it is advisable to include insulation between the back pan and the exterior cladding. This setup ensures that the dew point remains outboard of the back pan, enabling it to function as an effective air and vapour barrier.
Back pans are essential in providing a secondary defense against water infiltration, particularly for areas of the residential curtain wall panels that are not visible from the interior and are challenging to access.
In such opaque areas, water infiltration can go unnoticed for extended periods, leading to significant damage.
By employing back pans, potential water-related issues can be mitigated, preventing potential damage and costly repairs.
Additionally, back pans offer an advantage over foil vapour retarders, particularly in high-performance buildings with humidified environments. Foil vapour retarders can experience condensation, wetting, and failure in spandrel areas due to convection currents short-circuiting the insulation.
In contrast, using back pans helps avoid these potential problems, making them a preferred choice for building applications.
Shadow Boxes for Residential Curtain Wall Systems
Shadow box construction creates an illusion of depth behind a transparent glass pane in a curtain wall. It involves incorporating a metal sheet into the curtain wall behind the glass, positioned at least two inches away from the glass surface. This metal sheet can be painted or textured to add visual depth, with reflective surfaces offering the most pronounced effect.
To avoid potential problems, it is recommended to install insulation behind the shadow box if interior finishes prevent room air from coming into contact with this area.
Additionally, the system should be designed to collect any condensation that may accumulate on the exterior side of the metal sheet and effectively drain it back to the exterior.
However, implementing shadow box construction presents some challenges. Proper venting of the cavity behind the glass is essential to avoid dirt accumulation on surfaces that are difficult to clean. On the other hand, sealing the hole can ultimately lead to excessive heat buildup. The temperature inside the cavity may significantly differ from interior conditions, with only thermally conductive aluminum separating them. This temperature disparity can result in condensation or surfaces becoming dangerously hot.
To address these concerns, careful detailing is crucial. A well-designed system can thermally isolate the cavity from the interior, preventing issues like condensation or overheating. Furthermore, incorporating an interior back pan behind the insulation is recommended to avoid condensation on the metal shadow box from the interior.
Overall, thoughtful planning and consideration of these factors can result in a practical and visually appealing shadow box construction for curtain walls.
Support of Curtain Walls for Residential Facilities
Curtain wall systems must support their dead load and various live loads, including wind, snow, seismic, and maintenance loads. As the curtain wall may experience different movements from the building structure due to thermal changes and wind, the connections anchoring the curtain wall must allow for differential movement while resisting applied loads.
In stick-framed aluminum curtain walls, vertical mullions often run past two floors with specific anchor designs to accommodate standing and lateral movement. Large areas may introduce split vertical mullions periodically to address thermal movement. The glass units within the frame must also adapt to the surrounding aluminum frame movement, creating additional stresses in the system.
Unitized curtain wall systems are custom-designed to handle differential movement between the structure and frame. Proprietary assemblies with three-way dimensional adjustability anchor each curtain wall unit. These units resist lateral loads at horizontal stack joints and gravity and lateral loads at floor anchors. One of the floor anchors permits movement in line with the unitized system.