Prefabricated Roof for Houses

The use of prefabricated panels for house roofs offers the advantages of low cost and fast construction, but also presents issues such as waterproofing, earthquake resistance, and thermal insulation. The service life is approximately 30 - 50 years, with current efforts primarily focused on repair and renovation.

Advantages

• Low cost and fast construction speed: In rural self-built houses, the use of prefabricated cement panels as roofs was very common before the year 2000, mainly due to their low cost and fast construction speed, with installation possible in just one day or half a day. This is a significant advantage for users with limited budgets who wish to complete house construction as quickly as possible, saving both time and cost.

Disadvantages

• Prominent waterproofing issues: There is a high probability of rain leakage during waterproofing work. Among rural houses with prefabricated panel roofs, 8 out of 10 experience rain leakage. This is mainly because gaps easily form between the prefabricated panels, and if waterproofing treatment is inadequate, rainwater can seep into the house through these gaps, affecting the living experience.
• Weak earthquake resistance: Prefabricated panels should not be used in earthquake-prone areas due to their low earthquake resistance coefficient, which can easily lead to collapse. Existing prefabricated panel houses generally have weak earthquake resistance. Under earthquake action, the connections between the prefabricated panels may be damaged, leading to structural instability of the house and seriously threatening the safety of residents.
• Poor thermal insulation: Prefabricated panels have poor thermal insulation properties, resulting in high indoor temperatures in summer and low indoor temperatures in winter. In rural areas where multi-story houses are common, an additional layer of roofing material is often required on the floor slab to compensate for this drawback, which undoubtedly increases construction costs and complexity.

Service Life and Policies

The service life of existing prefabricated panel houses is approximately 30 - 50 years. With the development of building technology, cast-in-place concrete and prefabricated buildings are gradually replacing traditional prefabricated panel houses. Prefabricated buildings use modular factory-prefabricated components, with construction periods shortened by 30% compared to traditional methods. Since 2022, China has implemented a policy of old community renovations, focusing primarily on the repair and renovation of prefabricated panel houses, with only buildings that meet the criteria for dangerous houses being demolished.