Construction of Houses with Prefabricated Slab Structures

The construction of houses with prefabricated slab structures should follow standardized procedures, covering production, installation, treatment, and quality control, while also paying attention to existing issues and policy directions.

1. Production of Prefabricated Slabs

Prefabricated slabs are cement components produced in factories. During production, wooden models are nailed together, steel bars are arranged, and cement is poured to form the slabs, which come in two types: solid and hollow. Hollow slabs achieve lightweighting by reducing the concrete in non-load-bearing parts, making them suitable for scenarios with lower load requirements. During production, strict control over the spacing of steel bars and the cement mix ratio is necessary to ensure that the strength of the components meets design standards.

2. Pre-construction Preparations

1. Detailed Design and Production Coordination: Utilize BIM technology to optimize drawings, coordinate with PC component manufacturers in advance, arrange production according to the construction schedule, and plan transportation routes to avoid delays.
2. Substrate Treatment: Before installation, the top surface of the load-bearing wall must be treated. It should be watered and then leveled with high-grade cement mortar to ensure a flatness error of ≤3mm, preventing uneven stress on the prefabricated slabs due to an uneven substrate.

3. Installation of Prefabricated Slabs

1. Hoisting Specifications: When hoisting with hooks, the component should be lifted 1 meter off the ground and held still for 15 seconds. After checking that the lifting points are normal, it should be slowly moved to 1 meter above the working surface and then lowered at a reduced speed. Operators should guide the descent by holding the wall and use a mirror to observe whether the connecting steel bars align.
2. Support and Alignment: After lowering onto the shims, install diagonal supports and align the component with the installation position line, ensuring a deviation of ≤5mm before unhooking. During installation, bottom supports must be provided to prevent the prefabricated slab from bending or cracking due to insufficient strength.

4. Slab Joint Treatment

Slab joints are crucial for waterproofing and crack resistance. They should be filled with high-strength waterproof mortar and reinforced with alkali-resistant fiberglass mesh. The joint width should be controlled between 10-20mm. After filling, the surface should be smoothed and polished to ensure it is flush with the surface of the prefabricated slab, preventing future leakage or cracking.

5. Advantages of Prefabricated Buildings

1. Efficiency Improvement: Modular factory-prefabricated components shorten the construction period by 30% compared to traditional methods.
2. Quality Assurance: Factory production of PC components allows for precise control over the thickness and spacing of steel bar protection layers, reducing human errors.
3. Energy and Material Savings: External wall panels adopt a sandwich insulation system, avoiding the problem of insulation layer detachment in traditional buildings; composite slabs and external wall panels can replace some formwork, saving material costs.

6. Existing Issues and Policy Directions

Existing prefabricated slab houses generally suffer from weak earthquake resistance, poor sound and heat insulation, and have a service life of approximately 30-50 years. Since 2022, China has implemented a policy of renovating old buildings, focusing on repairs and upgrades and only demolishing buildings that meet the criteria for dangerous structures. The emphasis is on improving living safety and comfort through structural reinforcement, pipeline updates, and the addition of insulation layers.