How to Address Joint Leakage in GRC Exterior Walls? Leakage Treatment and Qinglong Group's Systematic Repair Solutions

Leaks at GRC exterior wall joints are usually caused by sealant aging and failure, backing material problems, unreasonable joint design, or excessive substrate movement. Qinglong Group's principle for handling such issues is "precise diagnosis, thorough remediation, and prevention of recurrence", and it has established a standardized repair process. First, a leak investigation must be carried out to determine the location and cause of the leak. Common methods include water spray testing and endoscopic observation of the internal condition of the sealant.

The core steps of repair work are "clean, fill, seal, protect". 1. Cleaning: The original failed sealant and backing materials (such as foam rods) must be completely removed down to the solid substrate, and the joint walls treated with a dedicated cleaner—this is key to ensuring the adhesion of the new sealant. 2. Filling: Closed-cell polyethylene foam rods of the appropriate size are refilled as backing to control the depth and shape of the sealant joint. 3. Sealant application: A highly elastic, highly weather-resistant silicone sealant (movement capability ≥25%) is selected and applied by professional workers using specialized tools, ensuring the sealant fully fills the joint and forms a strong bond with the substrates on both sides. For joints with greater movement, silicone-modified sealant (MS sealant) may be considered. 4. Protection: During the curing period of the sealant surface, take measures to protect against contamination and rain exposure.

In a renovation project for a long-established office building in Nanning, we addressed multiple joint leaks in its GRC curtain wall. Beyond replacing the sealant, we also found that the original joint width design was insufficient to accommodate local thermal deformation. We adopted a root-cause solution of "widening the joints and re-applying sealant", and conducted preventive inspection and treatment of all similar joints throughout the building, completely resolving the problem. Qinglong Group emphasizes that joints are the lifeline of GRC exterior wall waterproofing, and their maintenance and repair must be carried out by professional teams using professional materials.