Renovation of Old Houses with Prefabricated Panels

The renovation of old houses with prefabricated panels requires a comprehensive approach encompassing structural assessment, construction preparation, specific renovation measures, and construction sequence.

Structural Safety Assessment Before Renovation

The structural team will conduct a comprehensive assessment of the old house. They will focus on inspecting the crack width at the prefabricated panel production sites; special treatment is required if the crack width exceeds 0.3 millimeters. They will also check the connection status between the prefabricated panels and the ring beams; if the bolt corrosion rate exceeds 30%, replacement is necessary. This is because excessively wide cracks and severely corroded bolts can affect the structural safety of the house, and timely treatment can prevent potential safety hazards during subsequent renovations.

Construction Preparation Phase

Setting up a temporary support system is crucial. Steel pipe supports should be installed every 1.2 meters along the length of the prefabricated panels. At key nodes, H-shaped steel beams should be used to replace the existing steel beams, with the cross-section of the steel beams being no less than 200*200 millimeters. This measure provides stable support for the house during the renovation process, preventing structural instability due to demolition and other operations.

Specific Renovation Measures

• Roof Renovation: After removing the original wooden roof, a new concrete roof should be poured while maintaining the original height. This ensures waterproofing, enhances the durability and stability of the structure, and meets the requirements for laying various roofing materials after renovation.
• Exterior Wall Renovation: After removing the exterior wall tiles as a whole, repainting and reinforcing with steel bar grouting should be carried out. This strengthens the load-bearing capacity and tensile properties of the original walls, improving the overall stability of the house.
• Panel Seam and Structural Column Treatment: At the panel seam positions detected during the structural inspection, remove the original filling materials, implant No. 6 threaded steel bars, and pour C30 fine aggregate concrete. At the four corners of the house, add structural columns with a cross-section generally of 240*240 millimeters, reinforced with No. 6 and No. 8 steel bars, and connected to the floor slabs. These operations enhance the seismic performance and structural integrity of the house.

Construction Sequence

Adopt the principle of starting from the middle and then moving to the sides, carrying out segmented demolition and cutting while maintaining symmetrical demolition. The daily demolition volume should not exceed 30% of the total floor slab area. During the demolition process, continuously monitor the stress changes in the support system and prohibit the use of heavy hammer impact demolition to avoid shock and damage to the foundation structure. A reasonable construction sequence and strict demolition requirements ensure the safety and smooth progress of the renovation process.