Flat Roof Using Prefabricated Panels
Prefabricated panels can be used for flat roofs, but they have many drawbacks and are not recommended as the first choice. If the budget allows, it is advisable to use cast-in-place concrete roofs.
Production and Early Application of Prefabricated Panels
Prefabricated panels are cement components produced in factories. During production, a wooden model is first nailed together, and then steel bars are arranged and cement is poured to form the panels. In the field of rural self-built houses, before 20 years ago, prefabricated cement panels were a common choice for roof covering, mainly due to their low cost and extremely fast construction speed, with hoisting being completed in just one day or half a day.
Drawbacks of Prefabricated Panel Roofs
- Prominent Waterproofing Issues: The waterproofing performance of prefabricated panel roofs is poor, with a high probability of rain leakage. Among cases where prefabricated panels are used as roofs in rural areas, 8 out of 10 experience rain leakage. Even the professional waterproofing industry cannot guarantee 100% leak-proofness. This is because there are joint gaps between the prefabricated panels, which are the main channels for rainwater penetration. Over time, these gaps may further expand due to factors such as building settlement and temperature changes, exacerbating the rain leakage problem.
- Poor Earthquake Resistance: Prefabricated panels have a low seismic coefficient and should not be used in earthquake-prone areas. Under the action of an earthquake, the connections between the prefabricated panels are easily damaged, leading to the overall collapse of the roof and posing a serious threat to the safety of people and property.
- Poor Thermal Insulation: The thermal insulation performance of prefabricated panels is not good. The indoor temperature is high in summer and low in winter. To improve living comfort, it is generally necessary to cover the floor slab with secondary roofing materials, such as laying insulation boards or installing suspended ceilings, which undoubtedly increases construction costs and complexity.
Advantages of Cast-in-Place Concrete
With the development of construction technology, cast-in-place concrete has gradually replaced traditional prefabricated panels. Houses built with cast-in-place structures have better integrity and are sturdier, effectively avoiding the waterproofing, earthquake resistance, and thermal insulation problems associated with prefabricated panel roofs. In rural self-built houses, the choice of whether to use prefabricated floor slabs is mainly influenced by price factors. If money is not a major concern, it is recommended to use cast-in-place concrete roofs.
