Prefabricated Panels for Two-Story Houses

The use of prefabricated panels in two-story houses requires careful consideration of the pros and cons. While they offer cost advantages, they also have safety, durability, and functional deficiencies, necessitating comprehensive decision-making based on specific needs and regulations.

I. Significant Cost Advantages, but Beware of Long-Term Risks

Prefabricated panels, manufactured in factories and assembled on-site, reduce material and construction costs by over 50% compared to cast-in-place panels, making them particularly suitable for self-built rural houses with limited budgets. However, this cost advantage comes at the expense of some performance: due to construction technology limitations in the past, the lifespan of early prefabricated panel houses generally did not exceed 20 years. Existing houses often suffer from issues such as building cracks and water leakage, with potential repair costs offsetting initial savings.

II. Insufficient Safety and Seismic Performance

Prefabricated panels use thin cold-drawn steel wires (with a bearing capacity weaker than the #6 or higher steel bars used in cast-in-place panels), resulting in poor overall connectivity and a lower safety factor. Their seismic performance is particularly problematic: during earthquakes, prefabricated panels are prone to house collapse due to node loosening or fracture, as evidenced by the extensive damage to prefabricated panel houses in the 2008 Wenchuan earthquake. Additionally, the load-bearing capacity of prefabricated panel floors is limited; temporary stacking of heavy objects (such as the overloading on the second floor in the Chongqing Zhongxian incident) may trigger brittle fracture, posing a threat to life safety.

III. Poor Residential Comfort

Prefabricated panel houses have thin walls and poor sealing, resulting in inadequate sound insulation and thermal insulation. Indoor temperatures are easily affected by the outside environment in summer, while winter insulation performance is weak, necessitating additional reliance on air conditioning or heating, increasing energy consumption. The poor sound insulation of the floors means that noise from activities upstairs can easily disturb those downstairs, affecting the living experience.

IV. Renovation and Reinforcement Require Professional Support

To improve the performance of prefabricated panel houses, methods such as section enlargement reinforcement, carbon fiber cloth bonding reinforcement, or structural load transfer path modification reinforcement can be adopted, but these require assessment and construction by professional teams. If planning to install underfloor heating, dry underfloor heating (with a total weight of 30 kg/m²) is safer than wet underfloor heating (with a cement backfill layer of 150 kg/m²). If wet underfloor heating is chosen, a professional team is needed to calculate the floor load-bearing capacity and strictly control the backfill thickness to avoid overloading.

V. Policies and Industry Trends

Since 2022, China has implemented renovation policies for old buildings, focusing on repair and renovation of prefabricated panel houses and only demolishing buildings identified as dangerous. With the development of construction technology, cast-in-place concrete and prefabricated buildings have gradually replaced traditional prefabricated panel houses as the mainstream construction methods due to their safety, durability, and functional advantages.