How to Drill Holes in Prefabricated House Slabs

Drilling holes in prefabricated house slabs must be carried out by professionals. Unauthorized construction is strictly prohibited as it may damage the structure and lead to serious safety hazards.

I. Preparation Before Drilling

1. Confirm Slab Type: Ensure that the slab is a prefabricated one. Check the architectural drawings or use professional equipment (such as a rebar scanner) to detect the distribution of internal rebar and the direction of pipelines, avoiding damage to key load-bearing structures.
2. Determine Hole Parameters: Typically, the diameter of holes in prefabricated slabs should not exceed 8 centimeters, and the horizontal and vertical spacing should be maintained at more than 3 centimeters. The drilling location should avoid the two ends of the slab, the exact center, and areas with dense rebar. It is recommended to keep a distance of no less than 200 millimeters from the edge of the slab.

II. Selection of Drilling Methods

1. Mechanical Drilling: Preferably use a water-cooled electric drill or a diamond saw blade, which are suitable for straight, curved, or square holes. They offer high precision, fast speed, and low cost.
2. Special Methods: The drilling and blasting method is only applicable in extreme cases where mechanical tools cannot be used, but it is highly dangerous and requires strict risk assessment. Laser drilling (non-contact, high-precision) or manual drilling (suitable for small-batch needs) can be used as supplementary options.

III. Operating Specifications and Precautions

1. Probing Drilling: Use an impact drill to probe every 5 centimeters. If a regular hole 8 centimeters wide (possibly a rebar location) is encountered, stop immediately to prevent cutting the rebar.
2. Tool Control: Keep the tool stable, control the drilling speed, and clean up debris in a timely manner to avoid cracking at the edges of the hole or local damage to the slab.
3. Structural Assessment: If rebar is encountered during drilling, stop immediately and assess the impact on the structure. Consult a professional engineer if necessary.
4. Protective Measures: Operators must wear protective equipment such as goggles and dust masks to prevent debris from flying or dust from being inhaled.

IV. Post-Drilling Treatment

1. Edge Trimming: Check the edges of the hole and trim any burrs or cracks to avoid sharp edges from scratching pipelines or personnel.
2. Reinforcement Treatment: Large holes require the installation of reinforcement rings or the enhancement of local strength. When threading or installing pipelines, ensure proper waterproof and fireproof sealing.
3. Cleaning and Maintenance: Clean up impurities at the hole opening to ensure a flat surface and avoid residual debris affecting subsequent construction.

V. Safety and Compliance Requirements

1. Standardized Operation: Drilling must comply with building regulations. Unauthorized operation may violate regulations and affect the safety of the house.
2. Professional Consultation: It is recommended to consult a structural engineer or technician in advance to ensure that the plan is reasonable and legal, avoiding repair costs that far exceed the cost of drilling due to structural damage.