Renovation of Prefabricated Slab Buildings
The renovation of prefabricated slab buildings can be carried out through reinforcement, assessment, exterior wall and roof treatment, policy promotion, and the application of new technologies.
Reinforcement and Transformation, Wall Removal and Beam Replacement: For prefabricated slab buildings from the 1990s or those with a building age of 30 years, a temporary support system should be erected on both sides of the walls first. Steel pipe supports should be installed every 1.2 meters along the length of the prefabricated slabs, and key nodes should be supported with H-shaped steel beams with a cross-section of no less than 200200 millimeters. The slab joints found during structural inspections require the removal of the original filling materials, the insertion of No. 6 deformed steel bars, and the pouring of C30 fine aggregate concrete. Constructional columns measuring 240240 millimeters should be added at the four corners of the building, reinforced with No. 6 and No. 8 steel bars, and connected to the floor slabs. Construction should follow the principle of 'from the middle to the sides,' with the daily removal amount not exceeding 30% of the total floor slab area. During the removal process, the stress changes in the support system should be monitored in real-time, and the use of heavy hammers for impact is prohibited.
Comprehensive Structural Safety Assessment and Treatment: Before renovation, it is essential to focus on inspecting the crack width at the production points of the prefabricated slabs. Special treatment is required if the crack width exceeds 0.3 millimeters. The connection status between the prefabricated slabs and the ring beams should also be inspected, and bolts with a rust rate exceeding 30% should be replaced. The assessment results directly influence the choice of renovation plan. For example, if the cracks exceed the standard, local reinforcement or complete replacement may be necessary.
Exterior Wall and Roof Renovation: The original facing tiles on the exterior walls should be removed, repainted, and reinforced with steel bars and grouting to enhance the load-bearing capacity and tensile properties of the walls. For roof renovation, the original wooden roof should be removed, and a concrete roof should be poured while maintaining the original height to ensure waterproof performance and structural stability, as well as to meet the requirements for subsequent laying of different materials.
Policy-Driven Renovation: The new policy in 2025 clearly prioritizes the demolition and renovation of Grade D dilapidated buildings, prefabricated slab houses built before the 1980s, buildings with insufficient disaster resistance, and those affecting urban planning. The government provides compensation methods such as monetary compensation (not less than 110% of the market price of surrounding commercial housing), property rights exchange, and housing vouchers for resettlement to reduce resistance from residents regarding renovation.
Application of New Technologies: The E-MIC prefabricated concrete box house system showcased at the 2026 China International Fair for Trade in Services achieves simulation modeling of component disassembly, pipeline layout, and unit combination through digital and modular design. This shifts traditional operations to the factory in advance, improving standardized production levels and is suitable for urban renewal and old residential community renovation scenarios.
