Can Precast Slab Houses Still Be Used?
Whether precast slab houses can continue to be used depends on specific scenarios, with a trend towards phasing them out but not completely banning them yet. Their usage can be mainly categorized into the following three scenarios:
I. Rural Self-Built Housing: Gradual Phase-Out, Cast-in-Place Structures Preferred
In rural self-built housing, the application of precast slab floors is being replaced by cast-in-place concrete structures. The main reason is that precast slabs have the issue of joints being prone to cracking and leaking. Precast slabs are prefabricated in blocks and then assembled, and the joints are prone to developing cracks due to uneven settlement or material aging, leading to potential water leakage. Additionally, their poor sound insulation is a problem, as the thickness and material of the floor limit its sound insulation performance, affecting living comfort. Currently, some regions explicitly discourage the use of precast slabs as flooring and instead promote cast-in-place concrete structures, which form seamless floors through integral pouring, offering better earthquake resistance, waterproofing, and durability.
II. Urban Residential Housing: Gradual Phase-Out, Only Two Scenarios May Involve Demolition
The national approach to regulating urban precast slab houses is based on the principle of "safety first," adopting a strategy of "repair as the main approach, demolition as a supplementary measure." Only two scenarios may involve demolition: first, if the house is identified by a professional agency as having significant safety hazards (such as structural aging, insufficient load-bearing capacity, etc.); second, if the house is included in urban renewal or demolition planning. If the house itself is safe, it is usually extended in lifespan through reinforcement and repair rather than direct demolition. For example, some old residential communities enhance safety by adding seismic components and repairing cracks, allowing continued use.
III. Core Reasons for Safety Risks: Poor Earthquake Resistance, Material Prone to Fracture
The fatal flaw of precast slab houses lies in their weak earthquake resistance. Their structure consists of assembled blocks, and the connection points (such as steel bar anchoring and mortar bonding) are prone to fracture under seismic stress concentration, leading to floor slab detachment or overall collapse. Additionally, the material of precast slabs (such as early hollow slabs) has low shear strength and is prone to fracture under lateral forces. Historical earthquake data shows that the collapse and casualty rates of precast slab houses are significantly higher than those of cast-in-place structures, making them a key target for safety hazard remediation.
Summary: Whether precast slab houses can be used requires a comprehensive assessment of the scenario, safety, and policy requirements. For rural self-built housing, cast-in-place structures are recommended as a priority; for urban residential housing, if safe and not included in demolition planning, it can continue to be used after repair; for houses with safety hazards or planned for demolition, they should be handled according to policy.
