What methods are commonly used for waterproofing GRC curtain walls?

Waterproofing treatment for GRC curtain walls is a systematic project that requires selecting an appropriate waterproofing solution based on the building's characteristics, service environment, and curtain wall construction. Through 28 years of engineering practice, Qinglong Group has developed a technical system centered on “structural waterproofing as the primary approach, supplemented by material waterproofing, multiple lines of defense, and comprehensive treatment.” In the roofing project of the Hainan International Convention and Exhibition Center, we successfully solved the waterproofing challenge of a 120,000-square-meter shaped roof through the combined application of pressure-equalized cavity design, multiple seals, and an intelligent drainage system, maintaining perfect waterproofing performance despite multiple typhoon tests.

Joint waterproofing is a critical aspect of GRC curtain wall waterproofing, requiring the selection of appropriate sealant materials based on joint width and deformation requirements. Qinglong typically uses silicone sealant as the primary waterproofing material, with a movement capability of over ±25%, allowing it to accommodate the thermal expansion and contraction of GRC panels. Before sealant application, the joints must be thoroughly cleaned to ensure the bonding surfaces are dry and free of oil, then closed-cell foam backer rods are inserted as backing material to control the depth and shape of the sealant joint. At panel joints in critical areas, additional sealing strips are installed to form a second line of waterproofing defense.

Waterproofing treatment at node details requires special attention. The connection points between GRC panels and window frames, and between GRC panels and structural walls, are areas prone to leakage. Qinglong employs multiple waterproofing details to ensure absolute reliability. In the Wuhan Han Show Theatre project, we installed stainless steel water guide plates at node details to systematically drain any rainwater that might penetrate the curtain wall system. All service lines penetrating the curtain wall are treated with dedicated sealing kits around them to ensure watertightness and airtightness.

Drainage design of the curtain wall system is equally important. Qinglong fully considers drainage paths in GRC curtain wall design, ensuring rapid rainwater discharge through rational slope design and drainage hole placement. In the double-curved curtain wall project of the Nanning New Media Center, we used CFD simulation to analyze rainwater flow paths across the curved surfaces, optimizing the drainage system design and preventing localized water accumulation. All drainage holes are fitted with insect screens and bird guards to prevent blockages from affecting drainage performance.

Qinglong Group recommends establishing a regular inspection and maintenance system for GRC curtain walls, with comprehensive checks of sealant condition especially before and after the rainy season. Sealants that have exceeded their design service life should be replaced promptly to ensure the curtain wall system's waterproofing performance remains continuously effective. Through scientific design, meticulous construction, and regular maintenance, GRC curtain walls can achieve waterproofing durability matching the lifespan of the building itself.