Renovation Methods for Prefabricated Panels in Old Houses
The renovation of prefabricated panels in old houses requires a comprehensive consideration of structural safety, functional enhancement, and construction specifications. The specific methods are as follows:
Structural Safety Assessment Before renovation, a professional agency should be commissioned to conduct a comprehensive inspection, focusing on the crack width of the prefabricated panels (reinforcement is required if the width exceeds 0.3 millimeters) and their connection status with the ring beams. If the bolt corrosion rate exceeds 30%, they should be replaced with corrosion-resistant bolts; if the prefabricated panels exhibit severe aging or deformation, an assessment should be made to determine if a complete replacement is necessary.
Roof Renovation After removing the original wooden roof, while maintaining the original building height, a new concrete roof should be poured. The concrete should be added with a waterproofing agent and a drainage slope should be set to ensure waterproof performance; at the same time, installation interfaces for roofing materials (such as tiles, metal panels) should be reserved to enhance structural stability and durability.
Exterior Wall Treatment After removing the original exterior wall tiles, the wall should undergo reinforcement with steel bars and grouting: steel bars should be implanted vertically in the wall (with a spacing of approximately 300 millimeters), and high-strength grouting material should be poured to enhance the wall's tensile strength; the outer layer should be painted with waterproof mortar to prevent rainwater penetration and damage to the internal structure.
Panel Seam Treatment Remove the original filling material (such as cement mortar) from the panel seams and clean them to a solid base; implant No. 6 threaded steel bars (with a spacing of 200-300 millimeters), pour C30 fine aggregate concrete and vibrate it densely, and finally smooth it with waterproof mortar to prevent crack expansion and leakage.
Addition of Structural Columns Add structural columns at the corners and midpoints of the long sides of the house, with a cross-sectional dimension of 240*240 millimeters, internally configured with No. 6 and No. 8 steel bars (the diameter of the longitudinal steel bars should not be less than 12 millimeters, and the spacing of the stirrups should be 200 millimeters); the structural columns should be reliably connected with the floor slabs and ring beams to form an overall load-bearing system and enhance seismic performance.
Construction of Temporary Support System Before construction, set up steel pipe supports every 1.2 meters along the length of the prefabricated panels, and use H-shaped steel beams (with a cross-section of no less than 200*200 millimeters) for support at key nodes; the support system should be calculated to determine its load-bearing capacity to ensure that the floor slab does not deform or collapse during construction.
Construction Sequence and Monitoring Adopt the principle of 'middle first, then sides' to remove the prefabricated panels in sections, with a daily removal amount not exceeding 30% of the total area; during the removal process, monitor the stress changes of the support system in real-time, and prohibit the use of heavy hammers for impact; if foundation settlement or support displacement is found, construction should be stopped immediately and the plan adjusted.
Functional Upgrades To address poor sound insulation, 50-millimeter-thick soundproof cotton can be laid under the floor slab, or light steel keel soundproof panels can be installed; windows can be replaced with double-glazed units, and the gaps between the window frames and walls can be filled with expanding foam for sealing, effectively reducing noise transmission.
