How to Deal with Joint Leakage in GRC Exterior Walls?

Treating GRC joint leakage requires a systematic approach covering three aspects: design, materials, and construction. The "Three-Level Waterproofing System" developed by Qinglong Company for the Poly Peninsula No. 1 project in Hainan successfully controlled the leakage rate below 0.1%.

The design phase adopts the rainscreen principle, with 5-8mm dynamic joints set to allow thermal expansion and contraction of panels. By calculating wind pressure and thermal displacement values, the Mingyue Lake European Style Town project in Nanning precisely controlled joint width within a ±0.5mm tolerance, preventing sealant damage caused by deformation compression.

For material selection, the combination of "two-component silicone sealant + backer rod" is promoted. The high-elasticity silicone sealant can withstand 50% tensile deformation, while the closed-cell polyethylene backer rod prevents three-sided adhesion. Comparative tests show that this combination extends the service life 3 times longer than single-component sealant.

The construction phase innovatively adopts a contactless sealant injection method. A robotic arm equipped with a 3D vision system injects sealant at a constant speed along the joints with 0.1mm precision, eliminating the breakpoint problems of manual application. After the Qiangwei Garden project in Zengcheng, Guangzhou applied this technology, the joint pass rate increased from 85% to 99.6%.