Which waterproofing and drainage details are critical to prevent water ingress in a glass curtain wall?

Waterproofing is a fundamental engineering requirement for glass curtain walls because water penetration can cause structural deterioration, mold growth, and system failure. The façade relies on a pressure-equalized cavity system, allowing water to be managed before it reaches the interior. Properly designed joint seals, gasket compression, and drainage channels ensure water is directed outward. Key elements include weep holes, sill flashing, and back-up sealants that provide secondary protection if the outer seal is compromised. Mullions contain internal drainage paths that channel water away from the structure. Silicone structural sealants must be UV-resistant and tested to ASTM and EN waterproofing standards. Air leakage control is equally important since uncontrolled pressure differences can induce water intrusion. Field tests such as ASTM E1105 water penetration testing confirm system integrity before project handover. Proper installation sequencing ensures frame alignment, joint continuity, and anchor protection. When designed and installed correctly, the waterproofing system ensures long-term façade reliability and prevents expensive damage associated with water ingress.