Is Prefabricated Panel Used for the Roof of Small Flat Houses?

Single-story rural bungalows can use prefabricated panels, but their suitability needs to be evaluated based on specific needs. The following provides an explanation from four aspects: applicable scenarios, key considerations, construction points, and comprehensive suggestions.

Applicable Scenarios

1. Temporary Buildings: If rapid completion of the main structure is required (3-7 days for completion), prefabricated panels can shorten the construction period, making them suitable for temporary housing or transitional buildings.
2. Limited Budget: The cost of prefabricated panels is 30%-50% lower than that of cast-in-place structures, making them suitable for projects sensitive to costs.
3. Poor Geological Conditions: Soft soil foundations are prone to uneven settlement. Prefabricated panels, due to their light weight and good integrity, can reduce the risk of settlement.

Key Considerations

1. Load-Bearing Limit: The load-bearing capacity of a single panel is ≤200kg/㎡. If heavy objects need to be stacked on the roof or a second-floor addition is planned, cast-in-place structures should be used instead.
2. Joint Treatment: The gaps between panels must be filled with C20 fine aggregate concrete; otherwise, leakage may occur due to thermal expansion and contraction or vibration.
3. Seismic Performance: In areas with a seismic fortification intensity of 7 degrees or higher, steel structure reinforcement (such as adding ring beams and structural columns) is required; otherwise, cracking may occur during earthquakes.
4. Waterproofing Issues: The probability of leakage on prefabricated panel roofs is relatively high. An additional SBS modified asphalt waterproof layer should be laid, and a drainage slope (≥3%) should be set.
5. Poor Thermal Insulation: The thermal insulation performance in summer and winter is weak. Secondary covering with materials such as slag or foam boards is required, or an inverted roof design can be adopted.

Construction Points

1. Foundation Requirements: The ground should have a 30cm thick gravel cushion + a 15cm plain concrete leveling layer to ensure a flatness error of ≤5mm and avoid uneven stress on the prefabricated panels.
2. Installation Sequence: Install the panels block by block from the four corners of the house towards the center, using staggered joints (joint length ≥10cm) and grouting with cement mortar.
3. Material Selection: The commonly used specifications are length 3-6m × width 0.5-1.2m × thickness 12-18cm, with a strength grade not lower than C30, main reinforcement diameter ≥8mm, and spacing ≤15cm. Avoid using inferior recycled materials.

Comprehensive Suggestions
If the budget is sufficient and long-term safety and durability are pursued, cast-in-place concrete roofs are better (with good integrity and strong waterproofing and crack resistance). If conditions such as temporary use, low cost, or soft soil foundations are met, prefabricated panels can be an option, but joint treatment, waterproofing, and seismic issues must be strictly addressed, and the roof condition should be regularly inspected (e.g., every 2 years for the waterproof layer).