What Does Prefabricated Floor Slab in Houses Mean?

A prefabricated floor slab for houses is a concrete component pre-made in a factory, used for parts such as floor slabs and roof insulation layers in construction projects, and assembled on-site to complete the building structure construction.

Production Process and Types

The production of prefabricated slabs starts with building a wooden hollow mold. Steel bars are embedded inside as the framework. Then, cement is poured and dried to form a standardized component after the mold is removed. Based on structural differences, prefabricated slabs are divided into two types: solid and hollow:

• Solid prefabricated slabs: These are filled entirely with concrete, offering strong load-bearing capacity but being relatively heavy, suitable for scenarios with high structural strength requirements.
• Hollow prefabricated slabs: By reducing the amount of concrete in non-load-bearing parts to form a hollow structure, they achieve lightweight design and lower material costs, but have relatively weaker load-bearing capacity.

History and Application Scenarios

Prefabricated slab technology originated in the early 20th century. Due to its industrial production characteristics, it has been widely used in rapidly constructed residential projects. In China, most residential buildings constructed before 1985 adopted prefabricated slab structures, mainly for floor slabs and roof insulation layers. Its core advantages lie in efficient construction (direct transportation and installation after factory production), quality control (standardized production reduces human errors), and environmental protection and energy conservation (reducing on-site construction waste).

Characteristics of Prefabricated Slab Buildings

Prefabricated slab buildings are constructed by assembling components (such as wall panels, floor slabs, and beams and columns) produced in factories, and have the following characteristics:

• Short construction period: Component prefabrication and on-site construction are carried out simultaneously, significantly shortening the overall project duration.
• Low cost: Industrial production reduces material and labor costs, making it suitable for large-scale residential construction.
• Structural limitations: The connections between prefabricated slabs usually rely on cement mortar or simple steel bars, resulting in relatively weak integrity, leading to poor earthquake resistance and subpar sound and heat insulation effects.

Existing Problems and Renovation Measures

The service life of prefabricated slabs is about 30-50 years. As time goes by, their structural safety gradually decreases. Data from 2024 shows that 26.3% of old prefabricated slab buildings have had their safety improved through reinforcement renovations, which are divided into four levels of treatment:

1. Maintenance: Paint and rust-proof treatment are carried out on structurally intact prefabricated slabs.
2. Local reinforcement: Steel bars or carbon fiber cloth are added to reinforce prefabricated slabs with cracks or slight deformations.
3. Overall reinforcement: Supporting structures are added or external reinforcement plates are hung for buildings with insufficient load-bearing capacity.
4. Demolition and reconstruction: Severely damaged or unrepairable buildings are demolished and rebuilt.