Precast Concrete Slabs in House Construction

When using precast concrete slabs in house construction, it is essential to comprehensively consider their production, application scenarios, advantages and disadvantages, and recommendations to ensure safety and cost-effectiveness through proper planning.

Production Method

Precast concrete slabs are produced in a standardized manner at precasting yards: First, a hollow mold is made using wooden planks. A steel reinforcement framework is then placed inside the mold, followed by filling the hollow part with cement. After the cement has set and dried, the external wooden planks are knocked off, resulting in a concrete slab with internal steel reinforcement. This process gives the precast slabs a certain structural strength while ensuring dimensional accuracy through factory production.

Application Scenarios

Precast concrete slabs are widely used in construction:

• Rural Self-Built Houses: They are commonly used for floor slab installation. The lengths typically range from 3 meters to 4.2 meters (increasing in increments of 30 centimeters, with transportation difficulties beyond 4.2 meters). The widths can be either 50 centimeters or 60 centimeters, and the thickness is adjusted according to needs (12 centimeters for ordinary rooms, and 15 centimeters or more for load-bearing or second-floor rooms).
• Infrastructure: Such as cover slabs for roadside ditches and roof insulation layers, taking advantage of their lightweight and easy-to-install characteristics.

Analysis of Advantages and Disadvantages

• Advantages:
  • Low Cost and Fast Construction: Precast slabs are affordable, and construction teams can complete the assembly of a floor slab in half a day, significantly shortening the construction period.
  • Standardized Production: Uniform dimensions facilitate transportation and installation, making them suitable for large-scale applications.
• Disadvantages:
  • Poor Durability: After about ten years of use, they are prone to cracking and water leakage, requiring regular maintenance.
  • Weak Seismic Performance: Due to insufficient integrity, they are prone to fracture and collapse during earthquakes. Therefore, their use has been prohibited in modern commercial housing, and self-built houses should also carefully evaluate geological conditions.

Usage Recommendations

1. Damp-Proofing Treatment: Lay a damp-proof membrane during foundation construction (for limited budgets) or construct an elevated layer for the precast slabs (for sufficient budgets) to prevent moisture erosion and damage to the slab body.
2. Size Selection:
   • Length: Choose standard sizes ranging from 3 meters to 4.2 meters according to actual needs, avoiding custom-made extra-long slabs (high transportation risks and prone to fracture).
   • Thickness: Prioritize slabs with a thickness of 15 centimeters or more to ensure load-bearing capacity, especially for second-floor rooms or rooms storing heavy items.
3. Quality Control: Refuse to purchase precast slabs with insufficient thickness or non-standard lengths. Prioritize products from reputable manufacturers and verify whether the steel reinforcement layout complies with regulations.

Although precast concrete slabs are cost-effective and efficient, strict adherence to usage specifications, combined with damp-proofing, seismic resistance, and other measures, is necessary to balance cost and safety and extend their service life.