Prefabrication of Self-Built House Roof

The use of prefabrication technology for the roof of self-built houses offers advantages such as time-saving efficiency and low cost, but it also has drawbacks in terms of waterproofing, earthquake resistance, thermal insulation, and overall integrity.

Advantages

• Time-saving and Efficient: The prefabrication process is relatively simple and offers high construction efficiency. After workers prepare the cement mortar, they simply pour it lightly onto the roof base layer and spread it out, then use a straightedge to level it, ensuring uniform thickness. For larger roof areas, the work can be completed in a relatively short time, and the overall pouring results in a seamless, integrated structure without any拼接缝 (joint seams, here translated as 'joint seams' for clarity, though in context 'no拼接缝' means 'no joint seams').
• Low Cost: Prefabricated cement panels are inherently low in price, and the construction speed is fast. In rural self-built houses, using a prefabricated panel roof can be installed in just one day or half a day, and the sellers of the panels usually handle the installation process. For example, for a 40-50 square meter auxiliary building, the total cost of using panels is around 800 yuan, making it relatively cost-effective.

Disadvantages

• Waterproofing Issues: Prefabricated panel roofs have significant hidden dangers in terms of waterproofing, with a high probability of rain leakage. It is said that 8 out of 10 houses may experience rain leakage. The joints between two panels are the most prone to cracking and causing rain leakage, and currently, the waterproofing industry cannot guarantee 100% leak-proofing.
• Poor Earthquake Resistance: Prefabricated panels have a low earthquake resistance coefficient and are not suitable for use in earthquake-prone areas. In the event of an earthquake, due to their structural characteristics, they are prone to collapse, posing a threat to the safety of the house and its occupants.
• Poor Thermal Insulation: Prefabricated panels are generally about 12 centimeters thick and, although they are hollow structures, their thermal insulation performance is poor. In summer, the indoor temperature will be higher; in winter, the indoor temperature will be lower. Usually, a secondary roofing material needs to be applied on top of the panels to improve thermal insulation.
• Poor Overall Integrity: Prefabricated panels are made in advance and, when placed on the roof, are not integrated with the walls, failing to provide tensile and stabilizing effects. In the event of geological disasters or foundation settlement, they are prone to danger and may form roof cracks.