How to Renovate Prefabricated Buildings

The renovation of prefabricated buildings should follow scientific processes and standards to ensure that structural safety and functional upgrades are achieved simultaneously. The specific methods are as follows:

1. Comprehensive Structural Safety Assessment
Before renovation, a professional team must be commissioned to conduct structural inspections, focusing on key indicators such as the width of cracks in prefabricated panels (requiring reinforcement if exceeding 0.3 millimeters), the rust rate of connecting bolts between prefabricated panels and ring beams (requiring replacement if exceeding 30%), and the load-bearing capacity of walls. Technologies such as infrared thermal imaging and ultrasonic testing should be used to locate hidden dangers and form a detailed assessment report to provide data support for subsequent renovations.

2. Roof Renovation
After removing the original wooden roof, while maintaining the original height of the building, a new roof should be poured using C30 concrete. During pouring, a two-way steel mesh (with a diameter of not less than 8 millimeters and a spacing of 200 millimeters) should be set up to enhance integrity; the roof slope should be controlled at 2%-3% for drainage, and a base treatment layer for waterproofing membranes should be pre-embedded to ensure a tight bond between the waterproofing layer and the structural layer.

3. Exterior Wall Treatment
After removing the original exterior wall tiles, a three-step treatment is required:

• Base Cleaning: Remove loose mortar to a solid base and rinse the surface with a high-pressure water gun;
• Rebar Planting and Grouting: Plant No. 6 threaded rebars at intervals of 300 millimeters to a depth of not less than 100 millimeters and pour high-strength non-shrink grout;
• Plaster Layer Construction: Use anti-crack mortar for leveling, with a thickness controlled at 15-20 millimeters, and embed alkali-resistant fiberglass mesh (with a specification of not less than 160 grams per square meter).

4. Panel Seam Treatment
After removing the original filling material, clean the panel seams to a clean base, plant No. 6 threaded rebars (at intervals of 300 millimeters and a depth of not less than 50 millimeters), pour C30 fine aggregate concrete and vibrate it densely. During curing, cover with plastic film to maintain humidity and avoid cracking.

5. Adding Structural Columns
Add structural columns at key locations such as the corners of the building and stairwells, with a cross-sectional size of 240 millimeters × 240 millimeters, longitudinal reinforcement of 4 No. 12 rebars, and stirrups using No. 6 rebars at intervals of 200 millimeters. The structural columns need to form an integral frame with the floor slabs and ring beams. Before pouring, the contact surface should be chiseled and coated with an interface agent.

6. Demolition Construction Specifications
When setting up a temporary support system, steel pipe supports should be placed every 1.2 meters along the length of the prefabricated panels, and key nodes should be supported by H-section steel beams (with a cross-section of not less than 200 millimeters × 200 millimeters). Demolition should follow the principle of 'middle first, then sides,' with a daily demolition volume not exceeding 30% of the total floor area. Stress sensors should be used to monitor the deformation of the support system in real-time, and the use of heavy hammers for impact demolition is strictly prohibited.

7. Functional Upgrades

• Sound Insulation Treatment: Add 50-millimeter-thick sound insulation cotton to the walls and attach 12-millimeter-thick gypsum boards externally; use double-glazed windows (6 millimeters + 12 millimeters air layer + 6 millimeters) with frame bodies made of thermal-break aluminum alloy.
• Space Optimization: Adjust the layout of non-load-bearing walls according to the assessment report to add storage space or an open kitchen; if conditions permit, an elevator can be installed, requiring the reservation of a shaft location and compliance with fire safety regulations.