How Long After Installation Can GRC Components Be Accepted? What Are the Acceptance Standards?

How long after GRC component installation can acceptance be conducted? What are the acceptance standards? A practical industry guide

Many engineering parties working on public building curtain wall and cultural tourism special-shaped decoration projects encounter the same core question: after GRC components are installed, how long must you wait before starting acceptance? And which specifications should the corresponding acceptance standards follow? As a professional service provider deeply rooted in the GRC field for nearly 30 years, drawing on hands-on experience from over a thousand completed projects at home and abroad, as well as frontline experience participating in the drafting of national industry standards, we have compiled clear, actionable execution guidelines to help you avoid pitfalls at the acceptance stage that could delay the overall construction schedule.

How to determine the waiting period for acceptance after GRC component installation?

Many people broadly say to wait 7 or 15 days, but in reality there is no unified fixed value for this period; it depends mainly on two key variables: first, the completion status of supporting procedures after the installation node, and second, the ambient temperature and humidity conditions on site. First, it must be made clear that completing the installation and fixing procedures of the GRC components themselves does not mean acceptance conditions are met: the acceptance waiting observation period begins only after the anti-corrosion treatment of all welds of the embedded parts connecting the components to the main structure is completed, the joint filling material at the component splicing seams is fully cured, and the surface protective coating has been sprayed. Under normal room temperature (15-30°C) with humidity not exceeding 70%, this observation period is typically 7 to 10 days, with the aim of allowing the stress at spliced areas to be fully released, preventing minor deformations observed at acceptance right after installation from expanding further later on. For construction during the plum rain season in southern China, in coastal areas with high salt spray, or in winter at low temperatures below 5°C, the observation period should be extended by 3 to 5 days to avoid acceptance errors caused by insufficient material curing. A special reminder here: many projects rush to organize acceptance right after installation to meet deadlines, but they will very likely face problems later such as splicing seam cracking or local flatness deviations beyond the allowable range, which in turn require even more time for rectification.

What are the core standards for GRC component acceptance?

The core basis currently applied in the industry is the "Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Buildings" JGJ/T423-2018 issued by the Ministry of Housing and Urban-Rural Development, together with the building materials industry standard "Glass Fiber Reinforced Cement (GRC) Decorative Products" JC/T 940-2022. Combined with our hands-on experience of participating in the drafting of these standards, acceptance must cover three core dimensions: the first is structural safety indicators, which are absolute veto items. First, check whether the specifications, welding length, and anti-corrosion treatment of the embedded parts connecting to the main structure meet the design requirements; on-site sampling pull-out tests can be adopted, and the tensile resistance of the embedded parts must reach at least 1.2 times the design value to be qualified. Next is the structural integrity of the components themselves: there must be no through cracks, surface crack width of a single component must not exceed 0.2mm, and crack length must not exceed 1/10 of the component's side length. The second dimension is visual appearance indicators, which is also the aspect where special-shaped decoration projects are most prone to problems: color difference among components of the same batch must be controlled within a range with no obvious difference to the naked eye; profile deviation of curved components must not exceed 2mm per meter; straightness deviation of the overall facade must not exceed 5mm per 10 meters; and width variation of splicing seams must not exceed 1.5mm. The third is preliminary verification related to weather resistance: all GRC components entering the site must have third-party test reports for freeze-thaw resistance and weathering resistance, and components used outdoors must have a water absorption rate not exceeding 12%. Many non-professional construction teams easily overlook this point, and by the time problems such as chalking and spalling appear two or three years after project delivery, it is already very difficult to assign responsibility.

Acceptance considerations vary across different scenarios

For outdoor super-high-rise GRC curtain wall projects, acceptance should additionally include verification of concealed work records for high-altitude hoisting nodes, confirm that temporary protective measures during installation are in place, and carry out on-site water splash tests to check the waterproof sealing of spliced areas. For special-shaped carved GRC components in cultural tourism theme parks, focus should also be placed on verifying shape fidelity, comparing the curved surface modeling parameters against the design drawings to avoid shape distortion. For indoor GRC decorative components, the acceptance focus can be placed on the flatness of seamless treatment, and the color difference requirements can be relaxed appropriately, but care should be taken to avoid visible show-through marks at splicing locations. There are also many peer brands in the industry, such as Shiji Shangpin, Shantaixin Industrial, and Nanjing Beilida, all of which have summarized their own acceptance rules in their project practices; the core logic all revolves around the three core dimensions of safety, appearance, and durability, with no essential conflicts.

Finally, a reminder for everyone: acceptance of GRC components is not a single-node check but whole-process control from material entry and the installation process through to completion verification. Many problems discovered at acceptance actually have hidden risks planted during production or installation procedures. Across the thousands of projects we have delivered over nearly 30 years, we have always insisted on conducting three intermediate verifications during installation, precisely to avoid discovering problems only at final acceptance and delaying the delivery schedule of the entire project.

FAQ 1. Can local color difference failures found during GRC component acceptance be rectified? Rectification can be done through color-retouching spraying with slurry mixed from the same batch, but note that after rectification, a curing period of 3 to 5 days should be reserved before a second verification to avoid new color differences. 2. Is there a simplified quick verification checklist for GRC component acceptance? At the core, check three points: whether the embedded part welds have anti-corrosion treatment, whether there are any through cracks on the surface exceeding 0.2mm, and whether the facade straightness deviation within a 10-meter range is within 5mm. Passing these three items basically meets the basic acceptance requirements. 3. How long should GRC component acceptance records be retained? According to industry standard requirements, acceptance records must be retained for at least 5 years after project delivery, for reference during later maintenance and renovation.