Prefabricated Slab for Self-Built House Roof

Prefabricated slabs can be used for the roofs of self-built houses, but they have structural defects and functional deficiencies, requiring careful evaluation of applicability and the implementation of reinforcement measures.

1. Significant Economic Advantages, but Additional Investment Required

The core advantage of prefabricated slabs lies in their low cost and fast construction. For example, for a roof covering an area of 40-50 square meters, the total cost is approximately 800 yuan (including hoisting), and some suppliers offer hoisting services, enabling installation to be completed in 1-2 days. However, it should be noted that waterproofing construction must be carried out independently and cannot guarantee 100% leak-proof performance. After the rainy season, the effectiveness must be inspected, which may incur additional costs. Furthermore, their thermal insulation is poor, necessitating the additional covering of materials such as slag and lime to compensate for the lack of insulation, further increasing costs.

2. Prominent Structural Defects, Poor Earthquake Resistance and Stability

1. Poor Integrity: Prefabricated slabs are not integrally poured with the walls but are merely placed and connected, failing to provide tensile or stabilizing effects. In earthquake-prone areas, the roof is prone to collapse due to loose connections during earthquakes, posing serious safety hazards.
2. Severe Joint Problems: The joints between slabs are prone to cracking, leading to widespread roof leaks (statistics show that 8 out of 10 households experience leaks). If the foundation settles, cracks will form directly on the roof, further exacerbating the risk of leaks.

3. Insufficient Functionality, Reliant on Auxiliary Measures

1. Poor Thermal Insulation: The 12-centimeter-thick hollow floor slab has weak thermal insulation, resulting in high indoor temperatures in summer and low temperatures in winter. Covering with thermal insulation materials is necessary to improve insulation, but this increases the floor height and costs.
2. High Dependence on Waterproofing: Waterproofing construction must be carried out independently, and its effectiveness is greatly influenced by construction techniques, making it impossible to completely avoid roof leaks, which require regular maintenance.

4. Limited Applicable Scenarios, Strict Evaluation of Conditions Required

Prefabricated slabs are suitable for short-term use scenarios in non-earthquake-prone areas with limited budgets, such as temporary buildings or low-rise rural houses. In modern self-built houses, their usage has decreased, with more people opting for cast-in-place roofs (despite being 3-4 times more expensive) to avoid risks.

5. Usage Recommendations: Strengthening Reinforcement and Risk Avoidance

If economic conditions permit, prioritize the use of cast-in-place concrete roofs, which offer superior integrity, earthquake resistance, and waterproofing. If prefabricated slabs must be used, the following measures should be taken:

1. Strengthen joint treatment by filling with waterproof mortar or sealant;
2. Conduct strict waterproofing construction and inspect the effectiveness after the rainy season;
3. Cover with thermal insulation materials (such as slag and polystyrene boards) to improve insulation;
4. Avoid using in areas prone to geological disasters (such as earthquake zones and soft soil foundations).