Prefabricated Concrete House Floor Slab

A prefabricated concrete house floor slab is a type of house that uses prefabricated slabs as its floor. The prefabricated slabs include solid slabs and hollow slabs, which are pre-made in factories. They have the characteristics of low cost, short construction period, but poor integrity and insufficient seismic performance.

Production Process

When making prefabricated slabs, first nail a hollow mold with wooden boards. After laying steel bars in the hollow part of the mold, fill the hollow part with cement. After it dries, knock off the wooden boards.

Installation Process

• Preliminary Preparation: Before installation, block the holes in the floor slabs with concrete block plugs and then bend the floor slab steel bars upwards.
• Formwork Erection: For brick-concrete structures, hard-frame formwork erection is generally used. That is, first erect the formwork, install the floor slabs directly on the formwork, and then pour concrete after calibrating the dimensions.
• Steel Bar Treatment: After the floor slabs are hoisted onto the formwork, bend the floor slab steel bars downwards at a 45-degree angle so that the steel bars of adjacent floor slabs cross each other, and add a full-length steel bar in the middle.
• Support and Spacing: The distance that the floor slabs are supported on the wall is generally 8 centimeters. For example, if the wall is 240 centimeters thick, the floor slabs on both sides are each supported by 8 centimeters, leaving an 8-centimeter gap in the middle for pouring concrete. If a structural column is encountered during floor slab installation, a slab strip needs to be added.
• Calculation and Drawing: When calculating the number of floor slabs, calculate in advance the required quantity and installation positions of floor slabs of each width according to the drawings and floor slab dimensions, or draw a floor slab installation drawing.
• Slab Joint Treatment: The lower part of the slab joint spacing is 2 centimeters, and the upper part is 4 centimeters. This slab joint is poured with concrete after the main structure construction is completed and before pouring the floor concrete. If it is a cast-in-place concrete slab, this joint does not exist, or adding a slab strip between each floor slab can also be avoided.

Advantages, Disadvantages, and Regulations

Prefabricated slab houses have the advantages of low cost and short construction period, but they have the disadvantages of poor integrity and insufficient seismic performance. Their seismic level is usually lower than that of cast-in-place structures, and their service life is generally 30 to 40 years. In 2023, relevant Chinese departments stipulated that it is prohibited to newly build, renovate, or expand prefabricated slab houses and other buildings that do not comply with current regulations within the scope of urban construction land.