Rongchang Old Building GRC Exterior Wall Repair and Damaged GRC Panel Replacement Methods

GRC Facade Repair for Aging Buildings in Rongchang and Damaged GRC Panel Replacement Methods: A Professional Solution for Aging Building Facade Maintenance

In the process of urban renewal, the aging of facades on long-established older buildings has always been one of the core concerns of building owners, property management units, and urban operation and maintenance departments. Among these issues, the risks of damage, cracking, and detachment of GRC (glass fiber reinforced concrete) facades directly affect public safety and the integrity of a building's appearance. As a long-established industry enterprise with 28 years of full-chain UHPC/GRC/GRG/GRP service experience, the Qinglong GRC team has recently undertaken multiple GRC facade repair projects for aging buildings similar to those in Rongchang. Drawing on nearly 30 years of hands-on project experience, the team has developed a standardized, practical full-process solution for replacing damaged GRC panels, providing a reference for the maintenance of similar projects.

1. Investigating the Root Causes of GRC Facade Damage in Aging Buildings

Many staff responsible for the operation and maintenance of aging buildings wonder why GRC facades that met quality standards at installation and have been in service for less than 20 years are the first to develop bulging, cracking, and localized detachment problems. Based on field survey data from this batch of aging buildings in Rongchang, the root causes mainly concentrate in three dimensions. First is the limitation of early installation techniques: some GRC facade projects built in earlier years lacked adjustable allowances for thermal expansion and contraction, and after long-term exposure to local winter-summer temperature differences and rain erosion, internal stress in the panels gradually accumulated and eventually caused cracking. Second is the aging of the base bonding layer: conventional cement mortar bonding layers generally last about 15 years in outdoor environments, and in aging buildings the bonding layer has long since suffered powdering and delamination, directly causing the GRC panels to separate from the wall substrate. Third is differences in early raw material formulations: some batches of GRC panels had insufficient glass fiber content and inadequate impermeability treatment, and long-term rainwater infiltration caused the internal steel reinforcement to corrode and expand, further splitting the panel structure.

To address such issues, our first step after entering the site is never to directly begin the GRC facade repair work on the aging buildings in Rongchang. Instead, we first use 3D scanning equipment to conduct a full-coverage survey of the building's entire facade, marking all visible and hidden hollowing and cracking points while simultaneously collecting strength data of the base wall, so as to avoid recurring "repair again, fail again" problems in subsequent repairs.

2. Standardized Procedures for Replacing Damaged GRC Panels

For the damaged GRC panels of the aging buildings in Rongchang, we adopt a "precise localized replacement + overall performance reinforcement" approach rather than the traditional method of chiseling off and reinstalling the entire facade, which controls maintenance costs while matching the original facade's appearance to the greatest extent. The process is divided into four core steps: First is the safe dismantling of damaged panels. Before work begins, a fully enclosed warning zone is set up below the building, and the problem panels are removed by sectional cutting to prevent secondary damage to adjacent intact GRC panels from forceful knocking. After dismantling, the residual bonding layer and floating dust on the base wall are cleaned at the same time to ensure the substrate flatness meets installation requirements; Second is the prefabricated production of custom-matched GRC panels. Based on the dimensions, texture, and color code of the removed original panels, replacement panels of the same specification are produced on Qinglong's own standardized production line, with impermeability and weather-resistance pretreatment completed at the factory in advance to avoid substandard panel performance from on-site fabrication. For the special use scenario of aging buildings, we also add built-in rust-proof anchoring fittings inside the replacement panels to further improve structural stability after installation; Third is standardized installation. Abandoning the traditional pure cement mortar bonding technique, we adopt a dual fixing method of "bonding + mechanical anchoring" and reserve a 3mm thermal expansion and contraction gap for each replacement panel to prevent temperature changes from causing panel cracking again later. During installation, a level is used to calibrate flatness panel by panel, ensuring the joints between the newly replaced panels and the surrounding original panels are uniform and consistent; Fourth is joint treatment and overall protection. After panel installation, the joints are filled with flexible weather-resistant sealant and the surface is finished with color-matched texture treatment. Upon completion, a layer of transparent water repellent is uniformly applied to the intact GRC facade of the entire building to block rainwater infiltration channels and reduce the probability of future damage at its source.

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3. A Pitfall-Avoidance Guide for GRC Facade Maintenance of Aging Buildings

When choosing a GRC facade repair service provider, many managers responsible for the maintenance of aging buildings easily fall into the misconception of "looking only at the quote and not at capability", which ultimately results in inadequate repairs and re-cracking within six months. Based on our nearly 30 years of maintenance experience, two core points require special attention. First, confirm whether the service provider has full-chain GRC service capability. Some installation-only construction teams have no experience in GRC panel production and R&D, cannot match the material properties of the original panels, and the replaced panels are prone to color differences and texture mismatches. As an industry organization that participated in drafting the Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Buildings (JGJ/T423-2018), Qinglong has a standardized control system covering everything from raw material formulations to installation techniques, which can safeguard the consistency of repair results to the greatest extent. Second, clarify the boundaries of after-sales maintenance. GRC facade repair on aging buildings is semi-open-site work, and quality service providers offer an overall warranty period of at least 2 years covering common problems such as panel detachment and joint cracking, avoiding situations where no party takes responsibility when issues arise later.

From the perspective of industry development, as a large number of buildings with GRC facades built in China between 2000 and 2010 gradually enter their maintenance period, demand for this kind of localized repair and precise replacement will keep growing. As a leading enterprise in China's GRC field, Qinglong has always regarded full-cycle maintenance services as one of its core capabilities. In addition to GRC repair projects for aging buildings like those in Rongchang, Qinglong also provides regular facade inspection and maintenance services for many landmark buildings and commercial complexes, and has won the recognition of numerous owners and construction units thanks to its stable product quality and standardized service processes.

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