Renovation of Three-Story Prefabricated Panel Old Houses

The renovation of three-story prefabricated panel old houses can be achieved through frame reinforcement and upgrading, professional assessment and customized solutions, functional upgrades, and policy support pathways.

I. Frame Reinforcement and Upgrading
To address the issues of poor structural integrity and weak seismic resistance in prefabricated panel buildings, frame reinforcement technology can be employed. For example, in a project in Zhejiang, the original building was entirely reconstructed with a frame structure by raising it by 60 centimeters. The frame was poured first and allowed to fully solidify before the original prefabricated panels and walls were removed, ultimately achieving structural upgrading. In Xiantao, Hubei, prefabricated panel buildings from the 1990s were transformed into a frame system through overall structural reinforcement, with simultaneous maintenance of the main beams and columns, significantly enhancing structural safety. Such renovations require ensuring reliable connections between the frame and the original structure to avoid local stress concentrations.

II. Professional Assessment and Customized Solutions
Before renovation, a housing safety assessment must be conducted, focusing on detecting indicators such as wall cracks, steel reinforcement corrosion, and foundation settlement. Differentiated solutions are formulated based on the extent of damage:

• Wall Cracks: Cracks less than 0.3 millimeters wide are repaired with epoxy resin injection; cracks exceeding 0.5 millimeters or through-cracks require steel plate reinforcement.
• Roof Leakage: After removing the original waterproof layer, SBS modified asphalt waterproof membrane is laid anew, and a drainage slope is set.
• Unstable Foundation: For weak foundations, static pressure piles or root piles are used for reinforcement, with pile ends needing to penetrate the bearing layer by no less than 1.5 meters.

III. Functional Upgrades
To address the pain points of poor sound insulation and low space utilization in prefabricated panel houses, the following measures can be taken:

• Sound Insulation Optimization: Add 50-millimeter-thick sound insulation cotton to interior walls and replace exterior windows with double-glazed units (6+12A+6 specification), effectively reducing noise by over 30 decibels.
• Space Expansion: Combine with old residential area renovation policies to install elevators and add corridors on each floor to expand usable area; fire safety facility upgrades must comply with the requirements of the "Code for Fire Protection Design of Buildings", with the installation of standalone smoke detectors.

IV. Policy Support Pathways
Choose renovation methods based on the housing safety assessment grade:

• Grade A/B Houses: Include in the scope of old residential area renovations, focusing on exterior facade repairs and pipeline renovations.
• Grade C Dilapidated Houses: Enter the repair and reinforcement pathway, with central budget investments providing subsidies of no more than 70% of the total approved project investment, and local financial matching funds needing to be in place promptly. After renovation, third-party agency inspections are required to ensure compliance with safety standards of Grade B or above.