Cement Prefabricated House Roof

The cement prefabricated house roof is a type of roofing that primarily uses cement and prefabricated concrete as materials, available in various shapes and compressive strength specifications, with a typical design life of 50 years, and has its own advantages and disadvantages.

Materials and Shapes: The materials of the cement prefabricated house roof are cement and prefabricated concrete, with a rich variety of shapes, including rectangular, plate-like, elongated, square, circular, flat, irregular, and sheet-like forms, which can be selected according to different architectural needs and design styles.

Compressive Strength: It comes in numerous compressive strength specifications, such as 1.8mpa, 3.5mpa, 10mpa, 35mpa, 40mpa, 60mpa, 111mpa, 200mpa, 220mpa, 1000mpa, and 1860mpa. Prefabricated roofs with different compressive strengths are suitable for different architectural scenarios. For example, industrial buildings with high load-bearing requirements may choose specifications with higher compressive strength.

Design Life: Ordinary civil residences typically follow a 50-year design working life, and prefabricated panel houses are managed under the same criteria. Thirty years is not a mandatory retirement line; whether to demolish depends on professional safety assessment results. If assessed as Class A or B, they can be used normally; Class C requires local reinforcement; only Class D is treated as dangerous housing.

Usage:

• Advantages: Before 20 years ago, rural house construction favored using prefabricated floor slabs as roofing materials, mainly due to their low cost and ease of construction. Basically, using a crane to place the prefabricated floor slabs on the roof can complete the roofing in half a day, significantly shortening the construction period.
• Disadvantages: Most households using prefabricated panel roofs experience water leakage, generally requiring annual roof waterproofing treatment. However, waterproofing issues do not affect the service life of the prefabricated building; as long as the walls are stable, it can still be used for over 50 years. Additionally, prefabricated panels are made in the factory and transported to the site for hoisting, with mortar filling and node connections between panels, resulting in overall stiffness typically weaker than that of fully cast-in-place structures. In the event of earthquakes or uneven foundation settlement, panel joints, connections, and load-bearing walls are more prone to problems. Many prefabricated panel communities built quickly in the 1980s and 1990s had incomplete ring beams and constructional columns in some buildings, and the panel end connections and support lengths were not as strict as current standards, leading to issues such as roof leakage, fine wall cracks, and poor sound insulation between floors in these houses. If leakage is not repaired for a long time, the mortar in panel joints fails, and exposed steel bars rust and expand, further cracking the concrete.