Joints of House Prefabricated Panels

The joints of house prefabricated panels must be treated; otherwise, they may lead to water leakage, structural safety hazards, and sound insulation issues. The specific reasons and treatment methods are as follows:

Potential Problems

1. Water Leakage Risk
   When the joints are not treated, rainwater may seep into the interior along the gaps, causing mold on the walls, deformation of the floor, and even safety hazards such as circuit short circuits. For example, a shop in Changsha experienced the collapse of an entire wall and injuries to people due to unaddressed joint gaps.
2. Structural Safety Hazards
   Under external forces such as earthquakes, unreinforced joints become weak points in the structure, potentially leading to floor slab fractures or wall collapses. If the steel bars between the prefabricated panels are not effectively connected, the overall seismic performance of the house will be significantly reduced.
3. Reduced Sound Insulation Effect
   If there are gaps at the joints, sound can easily propagate through them, resulting in poor indoor sound insulation and affecting living comfort.

Treatment Methods

1. Basic Cleaning
   • Use a small shovel to remove debris and dust from the joints and rinse them clean with water to ensure the gaps are dry and free of impurities.
2. Gap Filling
   • Gaps ≤ 5 mm: Fill directly with cement mortar and compact and level it.
   • Gaps > 5 mm: Chisel the gaps into a 'V' shape to expand the contact area and then pour fine aggregate concrete to enhance the bonding force.
3. Steel Bar Reinforcement
   • If structural stability needs to be enhanced, use threaded steel bars with a diameter of ≥12 mm for reinforcement. The steel bars should span between two prefabricated panels and be fully embedded in the concrete.
4. Curing and Inspection
   • After filling, let it stand for at least 3 days, avoiding stepping on it or applying loads during this period to ensure the concrete fully solidifies.

Special Case Treatment (Horizontal Cracks)

1. Minor Cracks
   • If there are few cracks, the gaps are small, and there is no leakage, they can be left untreated for the time being as such cracks have little impact on structural safety.
2. Leaking Cracks
   • Chiseling Treatment: Chisel away 5 cm of the surface layer on both sides of the crack to form a sloped joint surface and roughen the surface of the prefabricated panel.
   • Layered Pouring: First, brush a layer of pure cement mortar with a water-cement ratio of 0.4 - 0.5, and then pour fine aggregate concrete in two layers (first pour to half the depth and second pour to 1 cm from the panel surface).
   • Post-repair Curing: After repair, cure for 2 - 3 days and strictly prohibit stepping on it.

Precautions

• Avoid Drilling: Do not drill holes in the prefabricated panels when treating cracks to avoid damaging the load-bearing structure of the floor slab.
• Construction Safety: If a ceiling needs to be installed on the prefabricated panels, the hanging rods should be fixed in the joints between the two panels to avoid directly penetrating the floor slab.