What Problems Can Non-Standard Reinforcement Around Screw Holes in Components Cause? Strengthening Failure Risks and Standardized Solutions

Non-standard reinforcement at screw hole edges of GRC components can easily lead to edge cracking, insufficient strength, loose connections, and other problems, seriously affecting installation stability and service life. Identifying potential risks and standardizing the reinforcement process are key to ensuring connection safety. Drawing on construction experience from multiple projects, Qinglong analyzes the core issues and rectification solutions.

I. Cracking and Damage at Hole Edges, Compromising Component Structure

Non-standard reinforcement at screw hole edges easily causes stress concentration under load, leading to cracking and damage. Without a reinforcement layer or with insufficient reinforcement area, local pressure at the hole edge becomes excessive when screws are tightened, causing the GRC substrate to crack; cracks extend from the hole edge and in severe cases run through the component, affecting its overall structural integrity. Improper selection of reinforcement materials, such as ordinary fiber cloth instead of dedicated alkali-resistant glass fiber cloth, or poor bonding between the reinforcement layer and the substrate, can cause peeling and detachment, increasing the risk of cracking. In the Guangzhou Zengcheng Qiangwei Garden project, Qinglong found that non-standard reinforced screw hole edges had a cracking rate of 15% after one year of use, requiring component replacement for rectification.

II. Insufficient Connection Strength and Reduced Load-Bearing Capacity

Non-standard reinforcement results in insufficient load-bearing capacity at screw hole edges, failing to meet design load requirements. Inadequate reinforcement layer thickness (standard ≥5mm) or insufficient fiber content reduces the tensile and shear strength of screw connections, making deformation and loosening likely during long-term use. An overly small reinforcement area that fails to cover the stress diffusion zone around the hole edge (standard reinforcement extends ≥50mm outward from the hole edge) prevents effective dispersion of stress concentration. Qinglong's test data show that the pull-out strength of properly reinforced screw hole edges is more than 40% higher than that of non-standard reinforcement—a significant difference in load-bearing capacity.

III. Waterproofing Seal Failure Leading to Corrosion Risks

Non-standard reinforcement at screw hole edges can cause poor bonding between the sealant and the component, leading to waterproofing failure. Uneven reinforcement layer surfaces with air bubbles or impurities prevent the sealant from fitting tightly, creating gaps through which rainwater and moisture penetrate the component interior, causing screw corrosion and GRC substrate weathering. Poor transition between the reinforcement layer and the screw hole edge, with steps or gaps, further increases the risk of leakage. In the Sanya Yingbin Yihao project, non-standard hole edge reinforcement caused seal failure with a screw corrosion rate of 20%, requiring re-sealing treatment.

IV. Widening Installation Deviations and Overall Curtain Wall Deformation

Non-standard reinforcement affects screw installation accuracy and triggers cascading deviations. Uneven reinforcement layer thickness at hole edges causes unbalanced forces during screw installation, resulting in tilting or displacement, with installation deviations exceeding the code requirement (±2mm). Inconsistent reinforcement across multiple screw holes causes overall tilting and misalignment after installation, leading to uneven curtain wall surfaces and irregular joints, and in severe cases affecting overall curtain wall stability. In the Nanning Wuxiang China Resources MixC One project, Qinglong controlled installation deviations within ±1mm by standardizing the hole edge reinforcement process, ensuring curtain wall installation quality.

V. Standardized Reinforcement Solution: Core Measures to Avoid Risks

Implementing a standardized reinforcement process eliminates various risks at the root. Use dedicated alkali-resistant glass fiber cloth and high-grade GRC mortar as reinforcement materials, with reinforcement layer thickness ≥5mm and fiber content ≥3%; the reinforcement area should extend ≥50mm outward from the screw hole edge to form a complete stress diffusion zone. During construction, ensure firm bonding between the reinforcement layer and the substrate, with a flat, smooth surface free of defects such as air bubbles and cracks. After installation, perform proper sealing to ensure the sealant fits tightly against the reinforcement layer. Through the standardized reinforcement process, Qinglong has reduced the incidence of screw hole edge quality issues to below 0.3%, effectively ensuring the connection safety and service life of GRC components.