Key Points for GRC Exterior Wall Junctions with Door and Window Openings: Detail Waterproofing and Qinglong Group's Joint Treatment Technology

The connection between GRC exterior walls and door/window openings is a critical waterproofing node, requiring adherence to the principle of “structural waterproofing first, material sealing as supplement,” with focus on three key points: “flashing design, sealing layers, and thermal deformation.” From major public building projects such as the Hainan International Convention and Exhibition Center and the Wuhan Hanxiu Theater, Qinglong Group has summarized standardized node practices: aluminum alloy flashing boards at the top of openings (overhang ≥50mm), 10-15mm deformation joints reserved on the sides, filled with polyethylene foam rods + silicone sealant (movement capability ≥25%), and drainage holes at the bottom. In the Shenzhen Yirui Biotechnology Building project, we detected and optimized 236 door/window opening nodes in advance through BIM modeling, achieving a 10-year zero-leakage record.

Flashing Design and Drainage Path

The flashing board should extend ≥30mm onto the inner side of the GRC panel, with a slope of ≥5%. Qinglong Group uses 3mm-thick fluorocarbon-sprayed aluminum alloy flashing, sealed with sealant at the GRC joints. In typhoon-prone areas, we add flashing fixing points (spacing ≤300mm), achieving wind uplift resistance of ≥3.0kPa.

Sealing Layers and Material Selection

A triple line of defense is formed: “outer sealant + hollow cavity + inner sealant.” The sealant has an adhesion strength to GRC of ≥0.5MPa and weather resistance of ≥25 years. We use two-component silicone sealant with adjustable curing time to adapt to site conditions. In the Nanning Wuxiang China Resources MixC One project, strict construction control ensured sealing quality.

Thermal Deformation and Tolerance Absorption

The reserved joint width is calculated using the formula W=α·L·ΔT+δ (δ taken as 5mm). Qinglong Group uses adjustable connectors that allow ±8mm three-dimensional adjustment. Through refined design, the unity of function and aesthetics is achieved.