Prefabricated Slab Roof Construction

The construction of prefabricated slab roofs must strictly adhere to regulatory requirements based on different roof forms to ensure structural safety and functionality.

Key Points for Prefabricated Slab Roof Construction in General Self-Built Houses

1. Material Selection:
   Prefabricated slabs should be purchased from reputable large manufacturers. The steel reinforcement must be prestressed, with a concrete strength of no less than C30, and the specifications and quantity of steel reinforcement must comply with national standards. During purchase, inspect the appearance to avoid defects such as cracks, honeycombing, or holes, preventing structural strength issues due to material quality problems.

2. Installation Specifications:

   • When placing prefabricated slabs on concrete components (such as ring beams), the bearing length should be no less than 80mm; when placing them on walls, the bearing length should be no less than 100mm to ensure support stability.
   • During installation, a gap of 20-40mm should be reserved between two slabs for subsequent seam treatment; the lower ends of the slabs should be bedded with cement mortar to enhance adhesion; the holes at both ends of the slabs in the wall should be filled with concrete to prevent rainwater leakage.
   • It is strictly prohibited to arbitrarily cut holes or slots in prefabricated slabs to avoid damaging the internal steel reinforcement structure; prefabricated slabs are not suitable for use in damp areas such as kitchens and bathrooms to prevent accelerated concrete carbonation due to long-term moisture exposure, reducing durability.

3. Seam Treatment:
   After thoroughly cleaning debris from the slab seams, pour cement mortar and vibrate it densely; if the seam is larger (exceeding 40mm), it should be filled with concrete and cured. It is forbidden to fill seams with bricks, as uneven shrinkage can easily lead to cracking and leakage.

4. Leak Prevention Measures:
   The roof should preferably use cast-in-place construction; if prefabricated slabs are used, a layer of steel reinforcement mesh should be laid on the roof, followed by pouring 6-8mm thick crushed stone concrete to form an integrated waterproof layer, enhancing impermeability.

Risks of Prefabricated Slab Slope Roof Construction

When directly laying 5-hole prefabricated slabs on a slope roof, although the end horizontal structure can prevent sliding, significant safety hazards exist:

• Poor Seismic Performance: Without seismic structural measures such as ring beams, prefabricated slabs can easily detach from the wall during an earthquake, leading to structural collapse.
• Insufficient Stability: The inclination angle of the slope roof amplifies the sliding risk of prefabricated slabs, and relying solely on end fixation is insufficient for long-term safety needs.

Recommendation: For slope roofs, prioritize cast-in-place concrete or light steel frame structures; if prefabricated slabs must be used, add seismic components such as ring beams and structural columns, ensure firm connection between the slabs and the wall, and conduct regular inspections and maintenance.