Renovation and Transformation of Prefabricated Slab Houses
The renovation and transformation of prefabricated slab houses require targeted measures based on the actual safety conditions of the houses. After being included in the scope of urban renewal starting from 2026, the main treatment methods include safety inspections, reinforcement and renovation, original demolition and reconstruction, and expropriation and resettlement. The specific approach needs to be comprehensively determined based on the danger level of the house, its renovation value, and the wishes of the residents.
I. Determining the danger level of the house is the core basis The treatment of prefabricated slab houses is not a one-size-fits-all approach. It is necessary to clarify the danger level through professional safety appraisals. Class C houses exhibit local load-bearing structures that do not meet safety requirements, posing local hazards. Class D houses, on the other hand, are in danger of the entire building due to the failure of load-bearing structures. The appraisal requires a comprehensive assessment of factors such as foundation settlement, the condition of load-bearing walls, beam-slab connections, concrete aging, water seepage and corrosion, and seismic resistance. The mere fact that a house is built with prefabricated slabs or its age cannot directly determine whether it needs to be demolished. For example, if the foundation is stable and the load-bearing structure is intact, even a prefabricated slab building can continue to be used through reinforcement.
II. Houses within the scope of demolition must meet the dual conditions of 'safety' and 'renovation value' Class D houses, due to systemic damage (such as foundation settlement, wall cracking, and beam-slab connection failure), result in high repair costs and difficult construction. They are usually prioritized for demolition and reconstruction, expropriation and renovation, or original demolition and reconstruction. Class C houses are mainly reinforced and repaired. If the building is severely aged, has concentrated functional defects, and the residents reach a consensus, it can also be included in the reconstruction scope. The specific approach needs to be determined based on the appraisal conclusions, planning conditions, financial capabilities, and the wishes of the residents. For example, some regions have formed diversified models such as 'original demolition and reconstruction funded by homeowners' and 'government expropriation and resettlement.'
III. Reinforcement and renovation must follow technical specifications and safety principles Taking the reinforcement of a 30-year-old prefabricated slab house as an example, a structural safety assessment must first be carried out, focusing on checking the width of slab joint cracks (treatment is required if exceeding 0.3 millimeters) and the bolt corrosion rate (replacement is required if exceeding 30%). During construction, a temporary support system should be erected (steel pipe supports should be set every 1.2 meters, and key nodes should be replaced with H-shaped steel beams). Threaded steel bars should be implanted into the slab joints and filled with C30 fine aggregate concrete. Construction columns should be added at the four corners of the house (with a cross-section of 240*240 millimeters, equipped with No. 6 and No. 8 steel bars) and connected to the floor slabs. During demolition, the principle of 'from the middle to the sides, symmetrically in sections' should be followed, with the daily demolition amount not exceeding 30% of the total floor area. The stress changes in the support system should be monitored in real-time, and the use of heavy hammers for impact demolition is strictly prohibited.
