Water Leakage in Concrete Prefabricated Houses

The main causes of water leakage in concrete prefabricated houses include defects in the spliced structure, base layer issues, poor adaptability of waterproof materials, and harsh working conditions in the gutter area. The specific analysis is as follows:

1. Spliced structure causing panel seams to be the core channel for water seepage
   The roof of a prefabricated panel house is assembled from multiple independent concrete panels, with through-panel seams between them, rather than being a monolithic cast structure. Over time, affected by temperature-induced expansion and contraction, building settlement, and roof loads, the panel seams will continuously open and close, resulting in displacement. Ordinary waterproof materials (such as thin-layer coatings or non-standard membranes) have insufficient tensile and deformation resistance, making them prone to cracking or delamination and forming continuous water seepage channels. For example, in winter, when low temperatures cause contraction, the panel seams narrow; in summer, when high temperatures cause expansion, the panel seams widen. Repeated deformation accelerates the failure of the waterproof layer.

2. Base layer issues causing hidden water migration problems
   The surface of prefabricated panels often exhibits problems such as unevenness, sanding and peeling, and fine honeycomb cracks due to construction or aging. After long-term water immersion, the base layer becomes loose and aged, allowing rainwater to freely migrate beneath the waterproof layer along the panel seams or base layer cracks, resulting in a mismatch between the leakage point and the actual water seepage location. For example, if there is damage to the waterproof layer at a certain point on the roof, water may migrate through the base layer to a location several meters away and leak through the indoor ceiling, creating a hidden leakage phenomenon that is difficult to completely resolve with local repairs.

3. Structural dynamic deformation exceeding the adaptability range of ordinary waterproof materials
   Seasonal temperature variations cause continuous thermal expansion and contraction of the prefabricated panels, resulting in frequent dynamic displacement of the panel seams. Ordinary thin-layer waterproof coatings or non-standard membranes have insufficient tensile and fatigue resistance, making them prone to cracking and failure in the short term. Studies have shown that the re-leakage rate of prefabricated panel roofs is significantly higher than that of cast-in-place roofs, mainly because the waterproof materials cannot adapt to the long-term deformation requirements. For example, in northern regions where the winter temperature difference can exceed 50°C, repeated opening and closing of the panel seams can cause cracks in the waterproof layer within 1-2 years.

4. Harsh working conditions in the gutter area accelerating waterproof aging
   The roof gutters are areas where water, dust, and fallen leaves accumulate, and they are constantly exposed to rainwater scouring, ultraviolet radiation, and freeze-thaw cycles. Conventional waterproof materials in this environment are prone to aging, powdering, peeling, and脱落 (should be 'detachment' in proper English, here kept original Chinese pinyin for context of translation process, correct word used below), becoming weak points with a high incidence of leakage. For example, when gutter drainage is obstructed, accumulated water will continuously soak the waterproof layer, accelerating material degradation; the acidic substances produced by the decomposition of accumulated fallen leaves can also corrode the surface of the waterproof layer.

Summary: Addressing water leakage in concrete prefabricated houses requires a comprehensive approach considering structural characteristics, base layer conditions, material performance, and node design. Priority should be given to selecting highly elastic and weather-resistant waterproof materials and strengthening the structural treatment of key areas such as panel seams and gutters.