Hazards of Rotten Prefabricated Floor Slabs in Houses

The decay of prefabricated floor slabs in houses can lead to various hazards, including structural instability, increased safety risks, and shortened service life, seriously threatening residential safety.

1. Almost zero earthquake resistance, prone to collapse during earthquakes
Prefabricated slabs have poor integrity and are not firmly connected to walls. During an earthquake, the floor slabs and walls can separate instantly, causing entire slabs to fall directly. For example, in many past earthquakes, prefabricated slab houses suffered severe collapses, resulting in a large number of casualties. Their earthquake resistance is far inferior to that of cast-in-place concrete structures.

2. Weak connection points, prone to structural instability
The connections between prefabricated slabs and walls, as well as between slabs themselves, are usually simple and lack reinforcement measures such as ring beams and structural columns. When the foundation settles or walls crack, the slabs are prone to misalignment and loosening. Over time, the connection points weather, and the steel bars rust, reducing strength. The floor slabs of old houses become precarious, and even slight additional weight or wall demolition can trigger a chain collapse.

3. Substandard materials, prone to breakage
To reduce costs, some prefabricated slabs use inferior materials, such as overly thin steel bars or even fine steel wires instead, and concrete with substandard grades or insufficient thickness, increasing brittleness. When overloaded, the slabs may break instantly. Daily stacking of heavy objects, renovation work that involves hitting the floor, or long-term aging can all cause sudden collapses.

4. Frequent cracks and leaks, affecting structural safety
Cracks are common in prefabricated slab houses, and roof leaks are particularly severe during the rainy season. Cracks not only affect aesthetics but also hide safety hazards, potentially leading to structural instability and increasing the risk of large-scale collapses or failures. Long-accumulated hazards can become 'fatal injuries'.

5. Short service life, premature 'aging'
The design life of prefabricated slab houses is typically 20 to 30 years. Over time, problems such as wall cracks, ceiling leaks, and floor slab deformations occur one after another. Many old prefabricated slab houses have been identified as 'Class C' or 'Class D' dangerous buildings, with high repair difficulty and cost, and some even require demolition and reconstruction.

6. Long-term unrepaired leaks further damage the structure
If roof leaks or wall cracks in prefabricated slab houses are not repaired promptly, the mortar in slab joints will fail, and exposed steel bars will rust and expand, further cracking the concrete. This vicious cycle accelerates structural damage and shortens the house's service life.