Solutions for Dampness in Prefabricated Houses

Dampness in prefabricated houses can be comprehensively addressed through indoor storage moisture prevention, foundation moisture prevention treatment, and daily moisture prevention measures.

Indoor Storage Moisture Prevention

If the house is at the construction site and conditions permit, heat-insulating materials and other items susceptible to moisture can be stored indoors. To prevent the increase in air humidity due to rainy weather from affecting the materials, indoor windows should be sealed to reduce the entry of external moisture into the indoor space.

Foundation Moisture Prevention Treatment

• Prefabricated Panel Elevated Moisture Prevention Method: Construct an elevated layer of prefabricated panels on the ground ring beam, leaving a 30 - 50 cm cavity between the foundation and the first-floor ground. When underground moisture rises to the cavity, it will dissipate and be unable to reach the first-floor ground, thus effectively preventing dampness on the first floor. During specific operations, after the ground beam is poured, control the height of the backfill soil at a distance of 30 - 50 cm from the ground and compact it. First, lay the prefabricated panels to form the elevated layer, adjust their positions to prevent misalignment, and then fill the joints with concrete. This method has good moisture and insect prevention effects and is durable. Although its price is slightly higher than that of earth backfilling, it is convenient for later floor pouring elevation and leveling, facilitating construction and preventing subsidence.
• Laying Moisture Barrier Film: Use high-density polyethylene film (PE film or geotechnical film) to block the upward movement of moisture from the ground. After the foundation is backfilled and compacted, lay a layer of fine sand and gravel on the surface, compact and level it, then lay the moisture barrier film, and finally pour a 10 cm thick concrete cushion or floor. This method has low cost, simple construction, and a short construction period, but its durability is limited. If there are sharp stones in the backfill soil or the film is torn during construction, moisture will penetrate through the breaks. In cases where the homestead is in a low-lying area, the groundwater level is high, or rainwater backflow occurs during the rainy season, a single layer of film is difficult to withstand the continuous moisture pressure. During construction, choose a high-quality film, use clean plain soil for foundation backfilling, overlap the film edges by no less than 15 cm, repeatedly paste the joints with waterproof tape, cut and fit the corners, turn up the film along the walls by at least 10 cm, and pour concrete as soon as possible after laying.

Daily Moisture Prevention Measures

Close the windows in the morning and evening and ventilate at noon. Reduce ventilation time when the external air is humid, especially close the windows tightly in the morning and evening when the external humidity is high, and open the windows appropriately for ventilation at noon on sunny days. Use quicklime for dehumidification. It has a good dehumidification effect and is inexpensive, but it is corrosive. Pay attention to preventing children from direct contact when using it. Place bamboo charcoal bags. Bamboo charcoal can adsorb excess moisture in the air and prevent mildew. It can be bought in supermarkets at a reasonable price and can be reused, but multiple bags are needed. Use a dehumidifier. This is one of the most effective methods and can effectively reduce air humidity. Use the air conditioner for dehumidification. Nowadays, many air conditioners have dehumidification functions. When the indoor humidity feels too high, this function can be turned on.