Prefabricated Slabs for Single-Story Flat Roof Houses

When using prefabricated slabs for the roof of a single-story flat house, it is essential to focus on their characteristics, construction key points, and maintenance issues, as detailed below:

Characteristics of Prefabricated Slabs

Prefabricated slabs are cement components manufactured in factories and come in two types: solid and hollow. Hollow prefabricated slabs achieve lightweighting by reducing the non-load-bearing concrete, lowering the structural self-weight while maintaining load-bearing capacity. Their production process involves: nailing wooden models → laying out steel reinforcement → pouring cement → curing and forming. Prefabricated slabs offer advantages such as standardized production and high construction efficiency but have drawbacks including weak earthquake resistance and poor sound and thermal insulation, which need to be compensated for through structural optimization or additional measures.

Construction Key Points

1. Damp-Proofing Treatment: In rural self-built houses, prefabricated slabs are often used to create an elevated damp-proof layer above the ground beam. The principle is to "exchange space for dryness," leaving a 30-50 cm cavity between the foundation and the first-floor ground. Underground moisture rises into the cavity and dissipates, preventing dampness on the first floor. The specific method involves: after pouring the ground beam, controlling the backfill height to 30-50 cm above the ground and compacting it, then laying prefabricated slabs to form the elevated layer.
2. Installation Specifications: Prefabricated slabs must be placed horizontally on supports, with support spacing conforming to design requirements (usually ≤1.2 meters) to avoid deformation due to excessive span. The slab joints should be filled with cement mortar to prevent rainwater leakage.
3. Structural Reinforcement: To address weak earthquake resistance, additional steel reinforcement can be added at the ends of the prefabricated slabs to connect with the ring beam, or a cast-in-place concrete layer can be used to enhance overall integrity.

Maintenance and Safety Assessment

1. Regular Inspections: Prefabricated slab houses require regular inspections of load-bearing structures, focusing on abnormal phenomena such as cracks and deformations. If 45-degree diagonal cracks in load-bearing walls, through cracks, continuously widening horizontal cracks in beams and slabs, or slab deflection occur, they should be immediately recorded and reported to the community or housing construction department.
2. Design Life and Decommissioning: The design working life of ordinary residential buildings is 50 years, and prefabricated slab houses are managed under the same standard. 30 years is not a mandatory decommissioning line. Whether to demolish depends on professional safety assessment results; if the structural safety performance meets standards, they can continue to be used.
3. Renovation Restrictions: Prefabricated slab houses should not be arbitrarily extended or have their load-bearing structures altered to avoid disrupting the original mechanical balance and causing safety hazards.

Prefabricated slab houses are widely used in rural self-built houses, but strict adherence to construction specifications and enhanced maintenance are necessary to ensure long-term safe use.