Prefabricated Floor Slab House

A prefabricated floor slab house is a type of building constructed using factory-prefabricated concrete slabs (including solid and hollow slabs) as the main components. It was once widely used to meet housing demands but is gradually being replaced due to technological limitations.

Construction Process and Structural Characteristics

The floor slabs of prefabricated floor slab houses are cast in a factory using formwork. First, wooden formwork is nailed together, steel bars are laid out, and then cement is poured. After drying, the formwork is removed to form the prefabricated slabs. During construction, prefabricated walls, floor slabs, and other components are transported to the site and assembled using equipment such as cranes, similar to assembling a “LEGO set”. For example, in rural self-built houses, using prefabricated components can complete the main structure within 14 days. Foundation piles are fixed with base plates, beams are quickly connected using mortise-and-tenon joints, stairs are hoisted and installed, a 5-centimeter-thick floor slab is laid, and finally, gaps are grouted. Hollow slabs achieve lightweighting by reducing non-load-bearing concrete but still have weaker overall integrity compared to cast-in-place structures.

Development History and Policy Restrictions

This building form originated in the early 20th century. In China, most residential buildings constructed before 1985 adopted this structure, primarily built in the 1970s and 1980s by state-owned enterprises or units to address housing needs for employees. With advancements in building technology, cast-in-place concrete and prefabricated buildings have gradually replaced traditional prefabricated slab houses. In 2023, the Building Energy Efficiency Regulations explicitly prohibited the construction, renovation, and expansion of non-compliant prefabricated slab houses within urban construction land. Since 2022, renovation policies have focused on repair and upgrading, with demolition only for buildings that meet hazardous building standards.

Advantages and Disadvantages Analysis

• Advantages: Low cost and short construction period. Building speed is fast and cost-effective, capable of quickly meeting large housing demands.
• Disadvantages: Poor overall integrity and lower seismic performance compared to cast-in-place structures; weak waterproofing and anti-seepage capabilities, with components prone to cracking and gaps prone to leakage; poor sound insulation and thermal insulation; relatively short service life (30-50 years), prone to aging and becoming hazardous when overdue; limited structural modifications, with load-bearing walls that cannot be removed and housing designs lacking in humanization (e.g., kitchens and bathrooms may lack windows).

Disposal Methods and Reinforcement Techniques

Current disposal follows the principle of “adapting measures to local conditions and implementing differentiated strategies”. Prefabricated slab houses with damaged main structures, unable to withstand disasters, affecting urban planning, or located in prime urban areas are prioritized for demolition, with compensation methods including monetary compensation, physical relocation, housing vouchers, and original-site reconstruction. There are two main reinforcement methods: First, the section enlargement reinforcement method, which involves pouring a reinforced concrete overlay with a thickness of ≥40 mm on the slab surface or bottom; second, the steel plate bonding method, which enhances load-bearing capacity by bonding steel plates to the surface of components using structural adhesive.