Waterproofing in the bathroom is a core element of the renovation process. While a water-tightness test can check the effectiveness of waterproofing, can it fully guarantee that the bathroom will never leak?
Here are some situations that may challenge your understanding:
Leakage occurs after some time of use:
Description: Everything seems normal in the first one or two years after renovation, but the bathroom starts leaking.
Possible causes:
Structural deformation: This causes the waterproof layer to tear. House movement or settlement exceeding the stretch limit of the waterproof materials can cause the waterproof layer to crack, leading to leaks.
Poor quality waterproofing materials: If low-quality waterproof coatings with poor water resistance and corrosion resistance were used, the waterproof layer may gradually fail over time.
Improper installation of drainage pipes: If the drainage pipes are displaced and not fully covered and fixed with cement mortar, and only waterproof coatings are applied, it may cause the waterproof layer to detach and lead to leakage.
Water-tightness test passes, but leaks occur right after moving in:
Description: Water seeps through the ceiling of the floor below, but the water-tightness test showed no issues.
Possible causes:
Improper construction: During floor leveling or tile laying, workers may remove protruding parts to fix issues with large corner radii, damaging the waterproof layer.
Non-compliant electrical and plumbing installation: When laying pipes, excessive foot traffic, especially at the corners, can damage the waterproof layer, causing it to fail.
Blackened door frame or damp door bottom:
Description: The bathroom door frame turns black, and the bottom of the door gets damp or deformed.
Possible causes:
Lack of a waterproof barrier: Some developers may not install a water-blocking ledge lower than the bathroom floor, which allows water to overflow through the gaps in the floor tiles. An additional water-blocking ledge needs to be installed during renovation to prevent this issue.
Waterproof layer not extended: If the waterproof layer at the bathroom door does not extend outward by at least 30 cm, moisture may seep around the door frame.
Wall moisture or mold growth:
Description: The bathroom walls show signs of moisture, and even the opposite wall may have mold spots.
Possible causes:
Uneven application of waterproof coating: If the waterproof coating is not applied evenly on the wall, small gaps may be left where water vapor can penetrate.
Floor moisture diffusion: If the bathroom entrance lacks proper waterproofing or a water-blocking ledge, moisture can seep through the gaps in the floor and affect the opposite wall, leading to mold growth.
Expansion at the bottom of the door frame:
Description: The bathroom door frame expands and deforms after absorbing water.
Possible causes:
Incorrect installation: If the "threshold stone" technique is not used, meaning the door frame does not rest on a threshold stone, moisture can seep into the bottom of the door frame, causing it to expand.
Summary and Suggestions:
High-quality waterproof materials must be used, and attention should be given to the application of the waterproof layer. The construction details, such as handling of drainage pipes, installation of water-blocking ledges, and the waterproof height at door openings, should be strictly followed. While the water-tightness test can initially verify the waterproofing, improper subsequent construction can still lead to leaks, so the entire renovation process needs to be carefully monitored. By perfecting every step, long-lasting waterproofing in the bathroom can be achieved.
