What is the construction process for renovating existing building exterior walls with UHPC panels?

Retrofitting the exterior walls of existing buildings with UHPC panels is a systematic renovation project aimed at enhancing a building's appearance, performance, and value. Its construction process must follow the principles of "precise surveying, safe demolition, efficient installation, and perfect finishing" to ensure minimal impact on the existing structure and residents. In multiple old residential community renovation projects in Guangzhou, Qinglong Group has successfully implemented a mature "rapid UHPC cladding panel renovation" method, transforming the traditional wet-trade facade renovation that once took months into an efficient parallel model of factory prefabrication and on-site installation, reducing the overall construction period by more than 40%.

Phase 1: In-depth surveying and integrated design are the prerequisites for success. First, a comprehensive survey of the existing exterior wall is required, including structural safety assessment, measurement of wall flatness and verticality, and confirmation of the positions of existing doors, windows, and pipelines. Qinglong adopts 3D laser scanning technology to quickly obtain precise point cloud data of the building facade, based on which the BIM detailed design of the UHPC panels is carried out. In this phase, the connection scheme between the new cladding keel system and the existing wall must be precisely designed (usually using post-installed anchors), while coordinating details such as insulation renewal, door and window finishing, and drainage and ventilation, to generate precise fabrication drawings and installation sequence diagrams.

Phase 2: Safe removal of the existing finish layer and substrate treatment. While the UHPC panels are being prefabricated in the factory, the old finishes (such as tiles and coatings) are demolished on site. Demolition must be carried out carefully to avoid damage to the main structure. After demolition, the substrate wall undergoes necessary repairs and leveling, and a new waterproofing layer is applied. The key in this phase is proper construction protection to prevent falling objects from causing injury, along with effective control of dust and noise to minimize the impact on residents in the building.

Phase 3: Keel system installation and dry-hanging of UHPC panels. According to the design drawings, the corrosion-treated light steel keel system is precisely installed onto the substrate wall using post-installed anchors. Once the keel installation is complete, flatness and verticality are rechecked. Then, following the numbered sequence, the factory-prefabricated UHPC panels are hung onto the keel via a stainless steel bracket system. The hanging process allows three-dimensional adjustment to absorb the construction tolerances of the existing wall. Qinglong's installation team is highly experienced, achieving a daily installation area of 50-100 square meters with exceptional efficiency.

Phase 4: Panel joint sealing, edge finishing, and final cleaning. After all UHPC panels are installed, weather-resistant silicone sealant is used to seal the panel joints, ensuring water-tightness and air-tightness. Precise edge finishing is carried out at junctions with doors, windows, roofs, floors, and other elements. Finally, the entire UHPC curtain wall surface is thoroughly cleaned, and the construction protection facilities are removed. The entire process is like dressing the building in a precisely tailored new coat—fast, clean, and efficient.