Top-Floor Precast Concrete Slab House

Top-floor precast concrete slab houses are buildings constructed primarily using precast concrete slabs and have certain issues. Currently, the focus is on repair and renovation, with only buildings that meet the criteria for dangerous structures being demolished.

House Characteristics and Origin

The precast concrete slabs used in top-floor precast concrete slab houses are factory-made concrete components. During production, wooden formwork is first nailed together, followed by the placement of steel reinforcement and the pouring of concrete. These slabs come in two types: solid and hollow. This type of housing originated in the early 20th century, and many residential buildings constructed in China before 1985 adopted this structural form. The advantages are significant, including low cost, a simple construction process, and a substantial reduction in construction time. These houses were once very popular in rural areas and became the preferred choice for many farmers when building their homes.

Existing Problems

• Weak Earthquake Resistance: Existing precast slab houses generally have weak earthquake resistance. Even a minor earthquake can potentially cause the building to collapse, posing a serious threat to the lives of the occupants.
• Poor Sound and Heat Insulation: The thickness of precast slabs is usually around 10 centimeters, and they have long circular holes in the middle. Due to their insufficient thickness and sound-conductive structure, their sound insulation ability is extremely poor. At the same time, their heat insulation performance is also inadequate. In summer and winter, the indoor temperature is greatly affected by the outside environment, resulting in low living comfort.
• Limited Service Life and Uneven Quality: The service life is approximately 30 - 50 years, and the quality of precast concrete slabs on the market varies greatly, with a large proportion being of inferior quality. These substandard products may trigger building collapse accidents without the occupants even realizing it, leading to casualties.
• Water Leakage Issues: There are tiny gaps between the slabs, allowing rainwater to easily seep into the interior of the precast slabs and corrode the steel reinforcement inside. This not only affects the structural safety of the building but also reduces its service life.

Current Situation and Handling Methods

With the development of building technology, cast-in-place concrete and prefabricated buildings are gradually replacing traditional precast slab houses. Since 2022, China has been implementing a policy of old building renovation, focusing on repair and renovation of precast slab houses and only demolishing buildings that meet the criteria for dangerous structures. Some regions have already started the demolition work.