What is the Name of the Prefabricated Slab on the Roof of a House

The prefabricated slabs used on the roof of a house are commonly referred to as 'prefabricated slabs' or 'concrete slabs', and in the context of rural self-built houses, they are also known as 'floor slabs'. The following provides an in-depth explanation from three dimensions: definition, manufacturing process, and application scenarios.

Definition and Classification

Prefabricated slabs are pre-made floor components in the construction field, representing a typical example of prefabricated building materials. Their core characteristic is the completion of the main structure through factory production or on-site prefabrication, followed by transportation to the construction site for installation. Based on material differences, they can be classified into two types: reinforced concrete prefabricated slabs (primarily made of cement, sand, gravel, and steel bars) and lightweight prefabricated slabs (such as aerated concrete slabs, GRC slabs, etc.). Among them, reinforced concrete prefabricated slabs are a common choice for roof structures due to their high strength and good durability.

Manufacturing Process

The production of prefabricated slabs involves three core processes: mold preparation, steel bar placement, and concrete pouring:

1. Mold Preparation: Standardized molds are made using wooden boards to ensure the dimensional accuracy of the components. The inner walls of the molds need to be coated with a release agent to facilitate subsequent demolding.
2. Steel Bar Placement: According to design requirements, steel bar meshes or prestressed steel bars are laid inside the molds. The diameter and spacing of the steel bars must comply with structural load-bearing specifications. For example, Φ6-Φ8 steel bars are commonly used in rural self-built houses, with a spacing controlled between 150-200mm.
3. Concrete Pouring: Concrete with a strength grade of C20-C30 is poured into the molds and compacted using a vibration table to eliminate air bubbles. After curing for 28 days, the slabs reach the designed strength and can be used. The application of prestressing technology can further enhance the performance of prefabricated slabs: by tensioning the steel bars and pouring concrete, and then releasing the prestress after the concrete hardens, the components generate reverse bending stress, thereby improving crack resistance and load-bearing capacity.

Application Scenarios

The application of prefabricated slabs exhibits significant era-specific characteristics and scenario adaptability:

• Early 20th-century buildings: As floor components, they were widely used in multi-story residential buildings, teaching buildings, and other projects. Their standardized production mode met the needs of industrialized construction.
• Rural self-built houses: In scenarios lacking large lifting equipment, prefabricated slabs are the preferred choice for roof structures due to their light weight per piece (usually 0.5-1.5 tons) and easy installation. For example, single-story residential roofs often use prefabricated slabs with a span of 3-6 meters, achieving structural integrity through wet connections (mortar bedding method) or dry connections (bolt fixation).
• Modern prefabricated buildings: With the development of building industrialization, prefabricated slabs have evolved into more complex prefabricated components (such as prefabricated hollow slabs, double-T slabs), but the traditional term 'prefabricated slabs' is still widely used.

It should be noted that prefabricated slabs have limitations such as complex joint treatment and relatively poor integrity. In modern construction, they are gradually being replaced by cast-in-place concrete slabs or new types of prefabricated floor slabs. However, they still offer advantages in terms of cost-effectiveness and construction convenience in specific scenarios.