When aluminum curtain walls utilize an open structure, the panel joints are not sealed with glue. While this improves aesthetics and airflow, it places higher demands on waterproofing. To effectively prevent rainwater from penetrating the internal structural layers, a comprehensive waterproofing system must be constructed from multiple dimensions, including the application of the isobaric principle, drainage system optimization, material selection and process control, structural reinforcement, and detailed attention to detail.
The isobaric principle is the core of waterproofing for open aluminum curtain walls. By incorporating pressure-balancing holes in the aluminum profiles, the pressure difference between the inside and outside of the curtain wall is minimized, significantly reducing the risk of rainwater infiltration due to pressure differentials. Specifically, small drainage holes are provided on the outer edges and lower portion of the profiles to create an isobaric cavity, allowing any small amount of seepage or condensation that enters the curtain wall to drain through the holes. Furthermore, air baffles are installed on each layer, acting as drains to remove condensation and seepage, while also separating the air to create an isobaric air cavity, further reducing pressure differences caused by height variations. This creates a dual protection mechanism of "isobaric + drainage."
A scientifically designed drainage system is crucial for waterproofing. Open aluminum curtain walls require comprehensive drainage pathways to ensure that any water that seeps through can be promptly drained. For example, gutters can be installed at the base of the curtain wall to divert accumulated water to the exterior. Alternatively, drainage panels can be installed on each floor, acting as air barriers to remove condensation and seepage in a layered manner. Furthermore, for vertically installed aluminum curtain walls, vertical drainage channels can be installed along the edges or in the keel system, with drain outlets spaced at regular intervals. For horizontally installed aluminum curtain walls, such as on roofs or awnings, horizontal drainage pathways should be designed, with drainage gaps between panels properly sealed with sealant. Gutters or gutters should also be installed along the edges to direct rainwater away from the building.
Material selection and process control directly impact waterproofing effectiveness. Aluminum curtain walls should utilize high-quality aluminum profiles, ensuring their strength, rigidity, and corrosion resistance meet design requirements. Surface treatment must comply with national standards. For example, the thickness of the anodized film must be at least AA15 to ensure proper sealant adhesion. High-performance silicone sealant should be used to ensure compatibility with aluminum profiles, glass, and other materials to avoid bonding failure due to incompatibility. During application, strict control of sealant application conditions is crucial, such as ensuring appropriate temperature and humidity, avoiding application during rainy or hot weather, and ensuring tight, bubble-free joints.
Structural reinforcement and detailed treatments are complementary measures for waterproofing. The aluminum panels of an open aluminum curtain wall can be attached to screw rods using hanging plates, with only the top edge secured in place with screws. This allows the panels to hang freely under gravity, improving their ability to withstand stress and resist thermal expansion and contraction. Furthermore, the inner rainproof barrier can consist of a waterproof backing sheet and thermal insulation. The insulation is secured to the backing sheet with cotton staples, and pinhole-shaped aluminum foil is placed behind it to evaporate any moisture and ensure it remains dry. Furthermore, drip lines or grooves can be machined onto the edges of the aluminum panels to effectively guide rainwater down the outside, preventing it from flowing back into the curtain wall.
Maintenance and management are crucial for long-term waterproofing effectiveness. Open-type aluminum curtain walls require regular inspection of sealant aging, and timely replacement of cracked or loose sealants. Drainage channels should be cleared of debris to ensure smooth drainage. The coating adhesion on the aluminum panels should be checked, and any areas of coating loss should be repaired. By establishing an effective maintenance and management system, the curtain wall's service life can be extended and maintenance costs reduced.
