Specification Requirements for Sealing Holes in House Prefabricated Slabs

The sealing of holes in house prefabricated slabs must strictly adhere to the following specification requirements to ensure structural safety and functional integrity:

I. Reinforcement Design Plan

1. Small Holes (≤300 mm)
   • If no more than 5% of the reinforcing bars are severed, no additional treatment is required; if more than 5% are severed, steel bonding or carbon fiber reinforcement must be used, with the reinforcement amount reaching at least 1.2 times the area of the severed reinforcing bars.
2. Medium-sized Holes (300-1000 mm)
   • Compensatory reinforcement or the addition of edge beams is required to enhance structural stability and prevent cracking due to local stress concentration.
3. Large Holes (>1000 mm)
   • The addition of cast-in-place concrete or structural steel edge beams is mandatory to alter the load path and ensure overall structural safety.

II. Construction Operation Specifications

1. Hole Drilling Requirements
   • Use a concrete cutting machine or core drill for hole drilling. Direct hammering is strictly prohibited to avoid damaging the internal reinforcing bars of the prefabricated slab or causing micro-cracks.
2. Hole Treatment
   • Before sealing, thoroughly clean the hole, roughen the original concrete surface to expose the aggregate, and insert reinforcing bars around the hole to enhance the bond between the new and old concrete.
3. Concrete Pouring
   • After formwork installation, pour concrete with a grade of C25-C30. Fill the hole in stages with fine aggregate concrete containing a micro-expansion agent, ensuring the surface is flush with the slab surface to reduce the risk of shrinkage cracks.
4. Curing and Protection
   • After pouring, cover with a protective film and cure for at least two weeks. After the concrete reaches the required strength, apply a leak-stopping compound and waterproof coating to prevent water penetration, which could lead to reinforcing bar corrosion or wall mildew.

III. Key Considerations

1. Material Compatibility
   • The sealing material must be compatible with the prefabricated slab material (e.g., concrete grade, expansion agent type) to avoid failure of the bond due to differences in material properties.
2. Professional Design and Construction
   • As the modification involves structural safety, the design and construction plan must be prepared by a professional reinforcement company or a certified structural engineer. Unauthorized operation by non-professionals is strictly prohibited.
3. Balancing Functionality and Aesthetics
   • After sealing, check the surface flatness and repair any aesthetic defects caused by construction to ensure the overall appearance of the building.

IV. Potential Risks of Unsealed Holes

If holes are not properly treated, they may become structural weak points, reducing the overall load-bearing capacity; water penetration can cause reinforcing bar corrosion and concrete carbonation, shortening the building's lifespan; and prolonged damp conditions can lead to wall mildew and detachment, affecting living health.

Strict adherence to the above specifications can effectively ensure the structural safety, waterproof performance, and service life of the house.