Renovation of Prefabricated Panel Buildings in Old Buildings

The renovation of prefabricated panel buildings in old buildings requires a comprehensive approach encompassing structural assessment, construction preparation, specific renovation measures, construction sequence, and policy utilization to ensure safety and compliance.

Structural Safety Assessment as a Prerequisite for Renovation

Before renovation, a professional structural team must conduct a comprehensive assessment, focusing on inspecting the width of cracks in the prefabricated panels. Special treatment is required if the crack width exceeds 0.3 millimeters. Additionally, the connection status between the prefabricated panels and the ring beams should be checked, and bolts with a rust rate exceeding 30% must be replaced. Constructional columns (with a cross-section of 240*240 millimeters) should be added at the four corners of the building, using No. 6 and No. 8 reinforcing bars for reinforcement and connecting them to the floor slab to enhance overall stability.

Construction Preparation Requires the Establishment of a Temporary Support System

Steel pipe supports should be installed every 1.2 meters along the length of the prefabricated panels, with key nodes using H-shaped steel beam underpinning (with a steel beam cross-section of no less than 200*200 millimeters) to ensure structural safety during demolition. For the panel joints, the original filling material should be removed, No. 6 deformed steel bars should be implanted, and C30 fine aggregate concrete should be poured to strengthen the joint connections.

Specific Renovation Measures Implemented by Section

• Roof Renovation: Without changing the original height, the wooden roof should be demolished and replaced with a newly poured concrete roof to improve waterproofing performance and structural durability, while also meeting the needs for laying various roofing materials.
• Exterior Wall Renovation: After removing the original exterior wall tiles, repainting and reinforcing with steel bars and grout should be carried out to enhance the load-bearing capacity and tensile strength of the walls, preventing cracking or peeling.

Construction Sequence Must Strictly Adhere to Regulations

The principle of "middle first, then sides" should be adopted, with segmented and symmetrical demolition. The daily demolition volume should not exceed 30% of the total floor area. During demolition, real-time monitoring of stress changes in the support system is required. The use of heavy hammers for impact demolition is prohibited to avoid shock damage to the foundation structure.

Policy Support Provides Opportunities for Renovation

The new regulations in 2025 specify that three types of prefabricated panel buildings should be prioritized for demolition: D-grade dilapidated buildings, buildings constructed before the 1980s, and buildings that are unable to withstand natural disasters or affect urban planning. The government offers various compensation methods, such as monetary compensation not less than 110% of the market price of surrounding commercial housing, property rights exchange that innovates traditional resettlement models, and the gradual implementation of housing voucher resettlement systems, providing residents with flexible choices.