How Good Is GRC's Waterproofing Performance? Impermeability Protection and Qinglong Group's System Solutions

GRC itself offers excellent waterproofing and impermeability performance, but its overall waterproofing effectiveness in projects depends on the organic combination of three factors: material properties, joint treatment, and system construction. The water absorption rate of high-quality GRC can be controlled below 6-10%, with an impermeability grade of up to P6-P8 (i.e., able to withstand 0.6-0.8MPa water pressure). Qinglong Group controls product water absorption within 8% by optimizing the mix ratio (low water-cement ratio, incorporating active admixtures such as silica fume) and applying a vacuum dewatering process, effectively blocking the penetration of liquid water. However, building waterproofing is a systemic issue: the waterproofing of GRC curtain walls or roofs relies more on the "rain screen principle" or "pressure-equalized cavity" design and the application of high-performance sealants. In the 120,000-square-meter hyperbolic roof project at the Hainan International Convention and Exhibition Center, we adopted a systematic waterproofing solution of "GRC panels + cavity drainage + multiple seals," achieving an outstanding record of zero leakage through ten years of rainy seasons.

Impermeability of the Material Body

The impermeability of the GRC matrix stems from its dense microstructure. Through carefully selected aggregate gradation, a reduced water-cement ratio (typically ≤0.35), and the addition of silica fume to fill micropores, Qinglong Group makes the capillary pores of hardened GRC tortuous and fine, greatly improving its impermeability. Testing shows that its impermeability pressure value can exceed 0.8MPa, superior to ordinary waterproof concrete.

Surface Treatment to Enhance Hydrophobicity

To further improve waterproofing performance, hydrophobic treatment can be applied to the GRC surface, such as brushing on a silicone-based water repellent. Without altering the appearance, this treatment increases the surface contact angle to ≥90°, creating a "lotus effect" that makes it difficult for rainwater to wet and penetrate the material. Qinglong Group routinely recommends such surface treatment for projects in coastal or high-humidity areas.

System Construction Is the Key to Waterproofing

No matter how well an individual GRC panel is waterproofed, panel joints remain the weak point. Rational joint construction must be adopted: providing drainage cavities, using highly elastic sealants with excellent weather resistance (such as silicone and MS sealants), and ensuring construction quality. Qinglong Group's curtain wall systems adopt open or closed waterproofing construction and come with complete joint detail design and technical guidance, solving waterproofing problems at the system level.

Qinglong Group has always upheld the concept of "systematic waterproofing," providing not only high-performance GRC panels but also complete waterproofing solutions covering design, materials, technology, and construction guidance, ensuring that the building's "skin" stays dry and healthy for the long term.