Prefabricated Slab Roof for Self-Built Houses
The prefabricated slab roof with a sloped cover for self-built houses has issues such as poor earthquake resistance, susceptibility to leaks, and poor thermal insulation. Moreover, the sloped cover may exacerbate these drawbacks. It is recommended to use a cast-in-place roof when economically feasible.
Poor Earthquake Resistance: The prefabricated slabs and walls are not an integral structure, lacking effective connection between them. During an earthquake, relative displacement can easily occur between the walls and the slabs, preventing the formation of a stable whole to resist seismic forces together. This makes the house highly susceptible to damage under seismic action, especially in earthquake-prone areas. Houses with prefabricated slab sloped roofs face higher safety risks, seriously threatening the lives and property of occupants.
Susceptibility to Leaks: The prefabricated slabs are independently manufactured and joined together on the roof using concrete or cement mortar. This joining method results in a roof that is not a continuous whole, with gaps at the joints. Over time, the house foundation may experience a certain degree of settlement, leading to cracks between the slabs and further exacerbating the leak problem. Relevant cases indicate that leak issues are relatively common in houses with prefabricated slab roofs, with possibly 8 out of 10 experiencing leaks. For sloped prefabricated slab roofs, the risk of leaks may be even higher due to the complexity of the slope and joints.
Poor Thermal Insulation: The thickness of prefabricated slabs is generally around 12 centimeters, providing limited thermal insulation. In summer, external high temperatures can easily transfer through the slabs to the interior, raising indoor temperatures and affecting living comfort. In winter, the opposite occurs, with indoor heat easily dissipating, resulting in lower indoor temperatures. To improve thermal insulation, secondary roofing materials usually need to be applied on the prefabricated slab floors, undoubtedly increasing construction costs and complexity. Sloped prefabricated slab roofs also suffer from poor thermal insulation, and thermal insulation treatment may be more difficult due to the special shape of the roof.
Given the numerous issues with prefabricated slab sloped roofs, it is recommended to use a cast-in-place concrete roof when economically feasible. A cast-in-place roof has good integrity, effectively improving the house's earthquake resistance, reducing the risk of leaks, and providing relatively good thermal insulation.
