Cast-in-Place and Prefabricated Floor Slabs in Building Construction

There are significant differences in construction methods, performance, cost, applicable scenarios, and identification methods between cast-in-place and prefabricated floor slabs in building construction.

Construction Methods:
Cast-in-place floor slabs require all processes to be completed on-site. Workers first erect formwork and bind reinforcement bars, then pour concrete, and remove the formwork after it solidifies. This entire process is similar to 'making a cake on-site', with a relatively long construction period. Prefabricated floor slabs, on the other hand, are produced as standardized cement slabs in factories in advance and are directly assembled and installed on-site after transportation, similar to 'assembling Lego blocks'. This method offers high construction efficiency and has lower requirements for the on-site environment.

Performance Differences:

1. Seismic Resistance: Cast-in-place floor slabs form a continuous structure through integral pouring, connecting tightly with walls and beams, providing strong seismic resistance and are less likely to collapse during earthquakes. Prefabricated floor slabs, due to their splicing method, have joints that can easily detach from walls during earthquakes, resulting in poorer seismic resistance.
2. Waterproofing: Cast-in-place floor slabs are solid structures without gaps, offering excellent waterproofing performance, especially suitable for wet areas such as bathrooms and kitchens. Prefabricated floor slabs have internal holes, and joints can easily become channels for water seepage, making waterproofing treatment difficult.

Cost and Construction Period:
Cast-in-place floor slabs require on-site formwork erection, pouring, and curing, resulting in higher labor and material costs, and are greatly affected by weather conditions, leading to a longer construction period. Prefabricated floor slabs, produced in factories, can reduce costs through scale production and are quickly installed on-site, making them suitable for projects with limited budgets or tight schedules, such as temporary buildings.

Applicable Scenarios:
Cast-in-place floor slabs, due to their good integrity, are widely used in high-rise residential buildings, large-span spaces (such as shopping malls and stadiums), and areas with high waterproofing requirements (such as bathrooms and kitchens). Prefabricated floor slabs are mostly used in low-rise buildings, temporary buildings, or projects with strict budgets, but require enhanced joint waterproofing treatment.

Identification Methods:

1. Age Determination: Houses built more than 15 years ago mostly use prefabricated floor slabs, while newly built houses after 15 years are mainly cast-in-place.
2. Structural Observation: If there are no beams above the walls or columns at the corners, it may be a prefabricated floor slab; conversely, if the walls are tightly connected with beams and columns, it is a cast-in-place slab.
3. Pipe Laying: Prefabricated floor slabs require reserved holes or columns for pipe laying, while cast-in-place floor slabs can have slots cut on-site.
4. Drilling Verification: Use an impact drill to make three holes 5 centimeters apart on the floor slab. If the drill enters a hollow space, it is a prefabricated slab (prefabricated slabs have holes with a diameter of 8 centimeters every 3 centimeters); if there is no hollow space, it is a cast-in-place slab.