[House Leakage Detection Method] Bathroom and kitchen floor tile leakage slope, drainage hole endoscope inspection and water pressure and air pressure testing practice

Leaking waterways and poor drainage: a house buyer’s nightmare

In the practice of house repair and inspection, water leakage and drainage disputes have always ranked first among consumer disputes. After renovating a new house or buying a new one, the most frustrating thing is that water accumulates on the bathroom floor when taking a shower, water overflows under the sink when washing dishes in the kitchen, and even less than a month after moving in, the neighbors downstairs come to complain that the ceiling is dripping. Bathrooms and kitchens are the areas in the house that use the most water and have the most complex water supply and drainage pipelines. To avoid these problems, extremely rigorous scientific testing must be done,andduring a home inspection.

Floor tile drainage slope detection: scientific measurement is better than sensory intuition

When many builders lay bathroom or balcony floor tiles, because the mud work method is not precise enough, the drainage slope of the floor is insufficient or even reversed (the position of the drainage hole is higher than the surrounding area), which will cause serious water accumulation problems. Taiwan's current building technical rules and construction specifications have clear requirements for wet areas (such as shower rooms, toilets without dry and wet separation, and work balconies). The drainage slope should usually be between 1/100 and 1/50 (that is, for every 1 meter of length, the height difference should be 1 to 2 centimeters).

[Testing Method] When inspecting a house, you cannot just use a ping pong ball to make a determination. Professionals will useor a digital electronic angle ruler to accurately measure the relative height difference between the surrounding floor tiles and the drain outlet. In addition, a "full water splash test" should be carried out: close the wet and dry separation door of the bathroom or use a water retaining strip to accumulate about 1 cm of water on the ground and let it sit for 30 minutes. Then remove the water retaining device and observe whether the accumulated water can be completely drained within 10 minutes and there is no residual water splash in the gaps between the floor tiles. If there is water accumulation, it means that the drainage slope is not in compliance, and the builder must be asked to re-lay the floor tiles in this area.

Endoscopic inspection of drainage holes: Preventing "convenient landmines" of builders' workers

Many newly built houses seem to have smooth drainage, but once residents move in and the flow of daily bath water increases, the drain pipes begin to back up. This is because during construction, workers often pour sewage containing fine sand and cement slurry directly into the ground when cleaning tiles and caulking. Or, plastic protective sleeves, or even drink cups and other debris are stuck inside the pipelines when they are being pulled.

[Endoscope Practice] In order to prevent such hidden problems, the use of endoscopes should be required during home inspections. Insert the high-resolution probe deep into each drainage hole (including bathroom floor drain, shower area drain, drain under bathtub, kitchen sink drain, balcony floor drain) and push it into the pipe at least 2 to 3 meters. Through the screen, hydropower engineers can clearly check whether there is cement residue, gravel accumulation, deformation and rupture of the pipeline, or water accumulation on the inner wall of the pipeline. Once it is found that more than 1/3 of the pipe diameter is covered with cement, it should be immediately recorded as a serious defect. The builder is required to entrust a professional manufacturer to use water jet cleaning or wall drilling to replace the pipes. The house must not be handed over directly.

Air pressure and water pressure testing of water supply pipelines: double insurance to prevent hidden water seepage

Most of the water supply pipelines (cold water pipes and hot water pipes) are buried in cement walls. Once the crimping is not tight or the pipelines are slightly cracked, water will penetrate at an extremely slow rate. It will only take a few months after moving in to form wall cancer on the wall next door. At this time, the wall must be built to repair, which is extremely costly.

During the completion of water and electricity and the inspection of the house, a pressure test of the water supply line must be performed:

• Hydraulic pressure test of the water supply system (sustained pressure test): Seal the water outlets of all faucets in the room, and use a press to drive water into the hot and cold water pipes so that the pressure reaches 7 to 10 kg/cm² (usually 2 to 3 times the operating pressure of general tap water). Close the valve, maintain the pressure for at least 1 hour, and observe whether the pointer of the pressure gauge drops in any way. If the pointer drops slightly, it means there is a slight leak in the pipe joint in the wall.
• Advanced air pressure test: The volume of air molecules in the air pressure test is much smaller than that of water molecules, and it is easier for them to escape from the extremely tiny crimping gaps of galvanized iron. Use an air pump to fill the pipe with 8 kg/cm² air pressure and let it sit for 24 hours. This is the most stringent international standard for testing concealed water supply projects.

Conclusion: Meticulously detect waterways to ensure asset safety

Waterway inspection in bathrooms and kitchens is an indicator of the construction quality of a house. For owner-occupiers, this can ensure peace of mind for the next ten years and avoid lawsuits with neighbors over water leaks; for investors who commercially acquire old houses to renovate Flip, this is the key to controlling the CapEx budget. During the home inspection stage, the most sensible and scientific property purchase strategy is to insist on using laser levels, pipe endoscopes and compactors for scientific inspections, and to include the test data in the home delivery acceptance list.