Part 2: Ground Seepage – The Nightmare for Ground-Floor Residents
Ground seepage mostly occurs in ground-floor units and basements. The moisture primarily comes from groundwater and dampness in the underlying soil, invading the interior through the floor structure and causing damp floors, sanding, and cracking. The specific causes include:
1. High Groundwater Level: If the groundwater level in the area is high, water will seep through the soil into the sub-base and foundation beneath the floor. When the floor’s waterproofing layer is damaged or missing, groundwater will wick upward, leading to damp floors. This is especially severe during the rainy season when the water table rises, potentially causing water pooling on the floor and seepage at wall corners.
2. Waterproofing Failure: Ground floors typically require a waterproofing layer during construction to block underground dampness. However, over time, this layer can crack or break due to aging, wear, or ground settlement. Additionally, inadequate thickness or improper installation during the initial construction (e.g., poorly overlapped membranes or missed spots in liquid coatings) can leave hidden vulnerabilities, allowing moisture to seep into the indoor floor.
3. Structural Floor Defects: If the concrete floor was poured too loosely or has cracks, or if the sub-base materials had high moisture content, underground dampness will diffuse upward through structural gaps. For instance, in some older houses without a sub-base, concrete was poured directly onto the soil. Shrinkage cracks in the concrete become pathways for moisture, causing the floor to feel perpetually sticky and damp.
Ground Dampness & Seepage: Targeted Solutions for Ground-Floor Residents
Since ground dampness and seepage predominantly affect ground floors, the solution must combine “waterproofing and moisture-proofing,” starting from the floor structure to completely block underground dampness and water.
1. Emergency Treatment: Quick Relief for Damp Floors
If major construction isn’t possible right now, you can alleviate the issue with these methods:
If major construction isn’t possible right now, you can alleviate the issue with these methods:
- Improve Ventilation: Turn on exhaust fans and dehumidifiers to accelerate moisture evaporation from the floor.
- Use Moisture Barriers: Lay down moisture-proof pads or carpets to reduce upward moisture diffusion and prevent direct skin contact with the damp floor.
- Apply Desiccants: Sprinkle desiccants (like lime powder or activated carbon) on the floor to absorb moisture. Remember to replace them regularly to avoid secondary pollution.
- Use Specialized Products: Apply BANDě inorganic waterproofing agents or BANDě wall/floor moisture-proofing agents.
2. Thorough Cure: Redoing the Floor Waterproofing & Moisture-Proofing Layer
This is suitable for severe dampness or active water seepage. The construction steps are as follows:
This is suitable for severe dampness or active water seepage. The construction steps are as follows:
- Step 1: Remove the decorative floor layer (tiles, flooring) until the base concrete is exposed.
- Step 2: Clean the floor by removing floating dust and debris. Use BANDě repair materials to fix floor cracks and fill gaps with sealant.
- Step 3: Create a moisture-proof layer. Soak the floor with BANDě waterproofing or moisture-proofing agents, or lay waterproofing membranes/liquid coatings. If the groundwater level is high, opt for BANDě penetrating crystalline waterproofing coatings. Crucial: Extend the treatment up the wall base by 30 cm to form a “moisture-proof closed loop.”
- Step 4: Lay a sub-base. Pour a fine-aggregate concrete sub-base over the waterproofing layer, level and compact it, and ensure a proper slope toward the drainage outlet.
- Step 5: Restore the decorative floor. When laying tiles, use grout to fill the joints to prevent moisture seepage. When installing flooring, lay a moisture barrier film over the sub-base before installation.
3. Basement Floor Dampness & Seepage: Specialized Treatment Plan
Basements are enclosed with poor ventilation, making dampness and seepage much worse. Extra waterproofing and ventilation measures are required:
Basements are enclosed with poor ventilation, making dampness and seepage much worse. Extra waterproofing and ventilation measures are required:
- Step 1: Waterproof both floor and walls. Use a “membrane + liquid coating” dual-waterproofing system for the floor. Wall waterproofing should be at least 1.5 meters high, with special attention to pipe penetrations and wall corners.
- Step 2: Install a drainage system. Set up drainage trenches and sump pits on the basement floor to remove standing water promptly. Install a submersible pump if necessary to automatically pump out water from the sump.
- Step 3: Enhance ventilation and dehumidification. Install industrial-grade dehumidifiers and fresh air systems to ensure indoor air circulation and maintain optimal humidity levels.
- Step 4: Add insulation. Install insulation layers on walls and floors to minimize temperature differences and prevent condensation-related dampness.
