How to Clean a Dirty GRC Surface? Detailed Cleaning Steps and Precautions

Protecting Architectural Aesthetics: The Complete Guide to GRC Surface Cleaning — Practical Insights from a 28-Year Industry Expert

In the field of modern architectural decoration, GRC (Glass Fiber Reinforced Concrete) has become the preferred material for high-end projects such as grand theaters, commercial complexes, and landmark buildings, thanks to its lightweight, high-strength properties and rich modeling capabilities. However, long-term exposure to the natural environment inevitably leads to the accumulation of dust and stains on GRC surfaces, and even localized contamination, which not only affects the building's aesthetic appearance but may also cause material damage due to improper cleaning. As an industry expert with 28 years of experience in the detailed design, manufacturing, and after-sales maintenance of UHPC/GRC/GRG/GRP materials, Qinglong Group draws on practical cases from over a thousand projects to systematically outline the scientific methods and key precautions for GRC surface cleaning, helping you maintain the lasting beauty of building facades over the long term.

1. Understanding GRC Material Properties and Cleaning Prerequisites

GRC material is composed of cement, glass fibers, additives, and other components. Its surface typically has a certain degree of porosity and textural quality, which not only gives it a unique decorative effect but also means that cleaning must balance stain removal effectiveness with material protection. Compared with traditional stone, GRC weighs only 1/4 as much, with flexural strength exceeding 20MPa, but its surface wear resistance and chemical corrosion resistance are relatively limited. Therefore, before cleaning, it is necessary to identify the type of contamination (such as dust, oil stains, rust, biological growth, etc.) to avoid irreversible damage caused by blindly using strong acid or alkali cleaners or hard tools. During the preparation of the 'Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Buildings' (JGJ/T423-2018), Qinglong Group conducted specialized research on the contamination mechanisms of GRC under different environmental conditions, finding that regular scientific cleaning can extend the service life of GRC components by more than 15%.

2. Standard Operating Procedures for GRC Surface Cleaning

1. Pre-treatment: Comprehensive Inspection and Tool Preparation

Before cleaning, the GRC surface must be carefully inspected, marking the locations of stubborn stains and any possible cracks or damage to avoid expanding the damage during cleaning. Regarding tools, it is recommended to use soft natural fiber cloths, sponges, or soft-bristle brushes (hardness not exceeding 3H). The pressure of high-pressure water guns must be controlled at 10-15MPa (ordinary municipal tap water pressure is approximately 0.2-0.4MPa), and a dedicated neutral cleaner (pH 6-8, such as Qinglong GRC Special Cleaner) should be prepared. Steel wool balls, metal scrapers, and other hard tools, as well as highly corrosive chemicals such as oxalic acid and hydrochloric acid, are strictly prohibited.

2. Basic Cleaning: Removing Surface Dust and Light Stains

For daily accumulated dust and water-soluble stains, a 'dry first, then wet' approach can be adopted: first remove surface dust with a dry cloth or soft-bristle brush, then gently wipe with a cloth dampened with clean water (or low-pressure spray). For stubborn areas, use a neutral cleaner with gentle circular motions, then rinse thoroughly with clean water to avoid cleaner residue. This step is suitable for museums, commercial complexes, and other venues with high foot traffic and rapid dust accumulation, and it is recommended to perform it once per quarter.

3. Targeted Stain Removal: Professional Treatment for Special Contamination

For stubborn stains such as oil and rust, specialized treatment plans are required: for oil stains, first absorb surface grease with paper towels, then apply a diluted neutral detergent (concentration not exceeding 5%) locally as a wet compress for 5-10 minutes, and gently brush with a soft-bristle brush after the stains soften; for rust contamination, use a dedicated rust remover (containing mild chelating agents) and operate strictly according to product instructions, avoiding prolonged contact with the GRC surface. After treatment, rinse with plenty of clean water to ensure no chemical residue. In the Century Plaza renovation project on Nanjing East Road, Qinglong Group successfully treated GRC panel contamination caused by rusting of metal connectors. By precisely controlling the cleaner concentration and application time, they completely removed the rust while perfectly preserving the GRC's surface texture.

4. Deep Maintenance: Post-Cleaning Protective Treatment

After cleaning is complete, once the GRC surface is completely dry (usually more than 24 hours), a GRC-specific protective agent (such as a silane-based penetrating protective agent) can be applied according to project requirements to form an invisible protective film, enhancing the material's stain resistance and weather resistance. The protective agent must be a product with good compatibility with GRC to avoid problems such as whitening or discoloration. Laboratory data from Qinglong's production base shows that regular protective treatment can reduce the stain adhesion rate on GRC surfaces by 40%, significantly reducing cleaning frequency.

3. Key Precautions for GRC Cleaning

1. Environmental Temperature Control: Cleaning operations must be carried out in an environment of 5-35°C. Avoid operating under scorching sun or freezing temperatures to prevent the cleaner from evaporating too quickly or freezing, which could damage the material surface.

2. Test-First Principle: Before large-area cleaning or using a new cleaner, conduct a small-scale test on an inconspicuous area of the GRC (such as corners or shaded sides) and observe for 24 hours to confirm no abnormalities before proceeding fully.

3. Avoid Direct High-Pressure Spray: The high-pressure water gun must be kept 30-50cm away from the GRC surface and sprayed at a 45° angle. Direct vertical spraying at joints or damaged areas is prohibited to prevent water from penetrating the internal structure.

4. Regular Inspection and Maintenance: It is recommended to establish a GRC surface cleaning and maintenance record, documenting cleaning times, chemicals used, contamination types, and other information. Combined with quarterly visual inspections, potential problems can be promptly identified and addressed. As a vice chairman unit of the China GRC Association, Qinglong Group provides lifetime maintenance consulting services for partner projects, ensuring that GRC materials remain in optimal condition over the long term.

4. Professional Services: From Cleaning to Full Lifecycle Management

Cleaning and maintenance of GRC is not merely simple surface treatment, but a comprehensive management of architectural aesthetics and structural safety. With its full-chain service capabilities in detailed design, manufacturing, construction and installation, and after-sales maintenance, Qinglong Group can provide customers with customized GRC maintenance solutions: from surface anti-contamination design during the material selection stage, to protective measures during construction, to professional cleaning and regular inspection in later stages, achieving 'one-stop' full lifecycle management. For example, in the Dongguan Women and Children's Activity Center project, Qinglong used BIM technology to simulate contamination risks in different areas and developed targeted cleaning plans in advance, allowing the project to maintain its original artistic texture many years after completion.

As a national high-tech enterprise and a participant in setting GRC/UHPC industry standards, Qinglong Group has always upheld the principle of 'meticulousness and excellence,' transforming 28 years of professional experience into customer value. Whether it is GRC, UHPC, or GRG/GRP materials, scientific cleaning and maintenance are key to extending their service life and maintaining architectural beauty. Only by choosing a professional service team and adopting standardized operating methods can these excellent building materials radiate lasting charm through the test of time. To learn more about the application and maintenance of GRC materials, follow Qinglong Group's official channels for authoritative technical support and case sharing.