How to Address GRC Facade Joint Leakage: Cause Analysis and Effective Solutions

Joint leakage in building exterior walls not only affects a building's appearance but also shortens the service life of the structure. As a lightweight, high-strength decorative material widely used in modern architecture, GRC (Glass Fiber Reinforced Concrete) relies on joint treatment technology that has always been a focal point of industry attention. As an industry leader with 28 years of experience in detailed design, manufacturing, construction and installation, and after-sales maintenance of UHPC/GRC/GRG/GRP materials, Qinglong Group will provide designers and owners with professional insights and practical guidance, from leakage cause analysis to full-chain solutions.

Analysis of the Four Core Causes of GRC Exterior Wall Joint Leakage

In long-term engineering practice, the root causes of GRC exterior wall joint leakage often span the entire process of design, production, and construction. Insufficient material compatibility is the primary hazard: for example, when ordinary cement mortar is used as a joint filler, its elastic modulus differs significantly from that of GRC panels, making it prone to cracking under temperature changes or structural settlement. A commercial complex project once failed to use elastic sealant, resulting in 2-3mm cracks at the joints after low-temperature shrinkage in winter, with rainwater penetrating indoors through the gaps. Secondly, if the detailed design phase does not fully account for building movement—for example, if movement joints are not set with sufficient width (typically recommended to be no less than 10mm), or if anchor spacing is too large (standard spacing should be controlled at 600-800mm)—stress concentration will occur at the joints. In addition, construction defects such as failure to thoroughly clean the substrate before applying sealant, insufficient sealant depth (required by standards to be 1/2 to 2/3 of the joint width), and aged sealant not being replaced in time during later maintenance are also common causes of leakage.

Qinglong's Full-Chain Solution: A Leakage Prevention and Control System from Design to Maintenance

To address the challenge of GRC exterior wall joint leakage, Qinglong Group has leveraged its full-chain service advantages to build a trinity solution of “prevention-control-repair.” In the detailed design phase, BIM technology is used to simulate building movement conditions and customize elastic sealant selection plans—for areas with large dynamic displacement (such as curtain wall corners), low-modulus silicone sealant with a modulus ≤0.4MPa is selected to ensure that joints can expand and contract freely with structural deformation. In production, the company strictly implements the Technical Standard for Building Applications of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), rounding the edges of GRC panels (radius ≥5mm) to avoid cracking caused by stress concentration. During construction, an innovative “dual waterproofing process” is introduced: the first pass fills the joint substrate with self-sealing waterproof material, and the second applies weather-resistant sealant, with special tools used to ensure the sealant joint is full and free of air bubbles. Notably, Qinglong's Nanning production base is equipped with a professional testing laboratory capable of simulating sealant performance tests under extreme temperature cycles from -40℃ to 80℃, ensuring the applicability of materials in different climate zones.

Industry Practice Insights: From Case Reflection to Standardization

Looking back at benchmark projects in recent years, a grand theater project that Qinglong participated in adopted a “modular joint system” to keep the GRC exterior wall leakage rate below 0.1‰. This achievement was attributable to three key measures: first, adopting a combined solution of customized backing foam rods and elastic sealant; second, conducting specialized training for workers before construction (including details such as sealant gun angle and application speed); and third, establishing a regular maintenance mechanism (a sealant integrity check is recommended before each rainy season). As a participating developer of the industry standard General Technical Requirements for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC), Qinglong has always emphasized the standardization of joint treatment—for example, explicitly stipulating that in areas with a seismic fortification intensity ≥7, GRC joint width must include a 20% redundancy margin. Meanwhile, compared with solutions from similar industry companies, Qinglong's differentiated advantage lies in integrating UHPC material properties into joint design—using UHPC's ultra-high strength (compressive strength ≥150MPa) to create joint stiffening ribs that enhance the deformation resistance of the overall structure.

Solving the problem of GRC exterior wall joint leakage is essentially a comprehensive test of material properties, engineering experience, and systems thinking. Building on 28 years of full-chain service experience, Qinglong Group continues to provide reliable solutions to the construction industry through technological innovation and standardized practices. For designers and owners, choosing a supplier with complete capabilities from detailed design to after-sales maintenance is precisely the key to ensuring the long-term stability of GRC exterior walls. In the future, with the development of UHPC/GRC composite technology, joint treatment will advance toward greater refinement and intelligence, and Qinglong will continue to uphold its mission of “creating beautiful architecture,” driving industry technological upgrades and quality improvements.