What Are Prefabricated Slabs on Houses

Prefabricated slabs on houses are a widely used floor form in early 20th-century architecture, primarily for building floors and roof slabs. The following provides a detailed introduction in terms of composition, manufacturing process, characteristics, usage history, and current status:

Composition and Manufacturing Process: Prefabricated slabs are concrete prefabricated components produced and processed in a prefabrication yard, composed of materials such as concrete and steel bars. During production, workers first build a hollow mold with wood, insert steel bars as the framework, pour concrete, let it dry, and then remove the mold. After being cast in molds, they are transported to the construction site for installation.

Characteristics:

• Advantages: They offer convenient construction and low cost, with high construction efficiency, enabling the completion of floor laying in a relatively short time. The quality is stable as they are uniformly produced in the prefabrication yard, ensuring consistent product specifications and quality. They are also environmentally friendly and energy-saving, reducing dust and noise pollution from on-site construction and having a high material utilization rate.
• Disadvantages: There are issues with gaps. Since prefabricated slabs need to be spliced together, gaps are prone to appear at the joints, affecting the overall integrity and waterproof performance of the floor. High dimensional accuracy is required; if there are significant dimensional deviations, installation difficulties may arise, affecting the quality of the floor. The sound insulation effect is limited. Due to the structural characteristics of prefabricated slabs, their sound insulation performance is not as good as that of cast-in-place floors. Their seismic resistance and overall integrity are relatively poor. Under external forces such as earthquakes, relative displacement is likely to occur between prefabricated slabs, leading to floor damage or even collapse.

Usage History: In the 1970s and 1980s, China was eager to build houses, and prefabricated slabs were widely used due to their low cost and fast construction speed. Approximately 2 trillion square meters were built across the country, equivalent to 12 million households living in prefabricated slab houses. However, their lifespan is generally 30 - 50 years. As they age, they can crumble like biscuits, are prone to collapse during earthquakes, and the joints often leak.

Current Status: Nowadays, the governance of prefabricated slab buildings is being promoted. According to building safety assessment reports, buildings are classified into four grades: A, B, C, and D. Different grades of prefabricated slab buildings have different treatment methods, such as renovation of old residential areas, repair and reinforcement, and expropriation and demolition.