Self-Built House Roof: Prefabricated Slab Tiling

When using prefabricated slabs for tiling the roof of a self-built house, it is essential to focus on the structural form, process selection, and defect management. The key points are as follows:

I. Structural Forms and Process Classifications

Prefabricated slab-tiled roofs typically use reinforced concrete slabs as the base layer, available in two forms: hollow slabs or cast-in-place flat slabs. The processes mainly fall into two categories:

1. Felt Leveling Layer Process: After laying a leveling layer on the surface of the prefabricated slab, cover it with felt, secure the felt strips and hanging tiles with wooden wedges, and finally lay the tiles. This process requires ensuring that the felt adheres firmly to the base layer to prevent water leakage due to improper joint treatment.
2. Waterproof Cement Mortar Tiling Process: Directly apply waterproof cement mortar on the surface of the roof slab and adhere the tiles to the mortar layer. This process is common in antique-style buildings and requires strict control over the mortar mix ratio and construction thickness to ensure a uniform mortar layer without voids.

II. Key Defects of Prefabricated Slab Roofs and Countermeasures

1. Waterproofing Issues: Joints between prefabricated slabs are prone to cracking due to structural settlement or temperature changes, leading to water leakage. In rural self-built houses, the leakage rate can be as high as 80%, primarily due to improper joint treatment or failure of the waterproof layer. Countermeasures:

• Fill joints with waterproof mortar or sealant and lay a reinforced layer of waterproof membrane.
• Maintain a roof slope of 20%-30% to facilitate drainage.
• Regularly inspect and repair aging waterproof layers.

2. Poor Thermal Insulation: Prefabricated slabs are typically 12 centimeters thick, resulting in high thermal conductivity and making the house cold in winter and hot in summer. Improvement can be achieved by adding a secondary insulation layer, such as cinder, expanded perlite, or extruded polystyrene board (XPS), with a recommended thickness of 5-10 centimeters.

3. Low Earthquake Resistance: Prefabricated slabs are assembled as a whole, with significantly lower earthquake resistance compared to cast-in-place concrete. They are prohibited in earthquake-prone areas, and in non-earthquake zones, structural measures should be strengthened, such as adding ring beams and structural columns, or using lightweight tiles (e.g., resin tiles) to reduce loads.

III. Key Construction Considerations

1. Check the flatness of the prefabricated slab before installation; if the error exceeds 5 millimeters, level it with cement mortar.
2. Adjust the spacing of hanging tiles according to the tile specifications, typically 300-400 millimeters.
3. When using cement mortar for tiling in antique-style buildings, reserve expansion joints (5-10 millimeters) between tiles to prevent cracking due to thermal expansion and contraction.
4. Install a parapet or water-blocking eave at the roof edge, with a height of not less than 300 millimeters, to prevent water backflow.

By selecting appropriate processes, strengthening defect management, and implementing strict construction control, the durability and safety of prefabricated slab-tiled roofs can be effectively enhanced.