What Is the Construction Process for Renovating Existing Building Facades with UHPC Panels? Complete Renovation Process Guide and Key Points

When renovating the exterior walls of existing buildings with UHPC panels, it is necessary to balance the structural safety of the old building, construction convenience, and the new appearance, following a standardized construction process to ensure renovation quality and efficiency. Drawing on experience from multiple old building renovation projects, Qinglong analyzes the complete construction process and key control points.

I. Preliminary Survey and Design Planning Phase

Thorough preliminary preparation is the foundation of a successful renovation and requires a comprehensive assessment of the old building's condition. On-site survey and testing: test the original exterior wall structure, including substrate strength, wall verticality, and structural stability; if the substrate strength is insufficient (concrete compressive strength <20MPa), reinforcement is required. Load verification: verify the load-bearing capacity of the main building structure based on the self-weight of UHPC panels (approximately 30-50kg/㎡) and wind loads, and add steel keels to share the load where necessary. Design plan formulation: determine the dimensions, shapes, and decorative effects of UHPC panels according to the building style and functional requirements, use BIM technology to simulate the installation process, and optimize panel segmentation and joint details. In the auditorium renovation project of the American International School of Guangzhou, Qinglong achieved precise renovation through BIM design.

II. Old Exterior Wall Removal and Substrate Treatment Phase

Standardized removal and substrate treatment create the conditions for UHPC installation. Old exterior wall removal: remove the original exterior wall materials (such as tiles, coatings, and old stone) in a “top-down” sequence, avoiding forceful demolition that could damage the main building structure, and clear debris and floating dust from the wall after removal. Substrate repair and reinforcement: repair wall cracks and hollow areas, level with polymer cement mortar with flatness deviation controlled within 3mm/m, and add steel mesh to aging walls to enhance overall integrity. Waterproofing treatment: apply a waterproof coating to the substrate surface, and add additional waterproof layers at leak-prone areas such as door and window openings and internal/external corners to ensure reliable substrate waterproofing. Qinglong adopts a double-layer waterproofing process in old building renovations to improve waterproofing performance.

III. UHPC Panel Production and On-site Installation Phase

Precise production and standardized installation ensure renovation results and safety. Factory prefabrication of components: produce UHPC panels at the factory according to design drawings, reserving anchor holes and joint grooves, with production tolerances controlled within ±2mm, and conduct quality inspection on each component before it leaves the factory. On-site installation preparation: erect safe scaffolding and protective netting, install steel keels (if required) with keel flatness deviation ≤2mm/m, and use 3D laser positioning technology to ensure installation accuracy. Component installation: install UHPC panels in the sequence of “bottom first, then top; corners first, then faces”, fixing them with a dry-hanging method at connector spacing ≤600mm, and adjust positions promptly after installation to ensure uniform joints (width 5-8mm). In an old office building renovation project in Shenzhen, Qinglong achieved an installation efficiency of 150㎡ per day.

IV. Sealing, Finishing, Acceptance and Maintenance Phase

Meticulous finishing and strict acceptance safeguard the quality of the renovation project. Sealing treatment: fill UHPC panel joints with closed-cell foam strips, then inject high-modulus silicone weather-resistant sealant to ensure full, bubble-free sealing with a smoothly finished surface. Decoration and protection: apply surface touch-up paint or protective coatings according to design requirements to improve appearance and durability. Acceptance and maintenance: carry out acceptance inspection in accordance with standards, covering indicators such as flatness, verticality, sealing performance, and anchor strength; after passing acceptance, establish a maintenance file and perform regular inspection and maintenance. Qinglong provides 5 years of free maintenance service after renovation to ensure long-term stability in use.