How to Waterproof UHPC Curtain Walls in Humid Regions?

Waterproofing treatment of UHPC curtain walls in humid regions must follow the core principle of the “rainscreen principle (pressure-equalized cavity design)”, building multiple lines of waterproofing defense: “panel waterproofing, joint water guidance, cavity drainage, and reinforced nodes”. Through project practice in high-humidity, rainy regions such as Hainan and Shenzhen, Qinglong Group has developed mature construction methods: adopting open-joint design (sealant joints serve only for air sealing), installing a continuous and complete waterproof breathable membrane behind the panels, and providing drainage holes at the bottom of the cavity; the panel joints are designed with a structure of “outer sealant (weather-resistant sealant) — middle cavity — inner waterproof breathable membrane”, using gravity and air pressure difference to guide infiltrated water out. In the coastal roof project of the Hainan International Convention and Exhibition Center, this waterproofing system has withstood ten years of typhoons and rainstorms with zero leakage. The key to successful waterproofing lies in a system design where “guiding” prevails over “blocking”.

The Rainscreen Principle and Pressure-Equalized Cavity Design Are Fundamental

A ventilated and drained cavity (typically ≥40mm wide) is provided between the UHPC panels and the interior wall. By opening vent holes at appropriate locations, the air pressure inside the cavity is basically balanced with the outdoor wind and rain pressure. In this way, even if a small amount of water penetrates, it cannot go further due to the absence of a pressure difference, and flows along the surface of the waterproof membrane to the bottom and drains out.

Water-Conducting Performance of Panel Joints Is Crucial

Horizontal joints should adopt “rabbet joint” or “stepped joint” designs, using gravity for self-drainage. Vertical joints are equipped with drainage channels. The sealant mainly serves for air sealing; select silicone sealant with good elasticity (movement capability ≥25%) and excellent durability.

Reinforced Treatment of Key Nodes Cannot Be Overlooked

Areas such as parapet copings, window openings, and wall-penetrating pipes are weak points in waterproofing and require additional reinforcement with waterproof membranes to form a complete waterproofing closed loop. We prepare detailed node drawings to guide construction.

Scientific waterproofing design makes UHPC curtain walls indestructible in humid environments. Qinglong Group provides lifelong waterproofing protection for buildings through systematic solutions.