Waterproofing for the Bottom of Prefabricated Houses

There are two methods for waterproofing the bottom of prefabricated houses: waterproofing for the elevated floor of prefabricated panels and waterproofing for the horizontal joints at the bottom of prefabricated exterior walls.

Waterproofing for the Elevated Floor of Prefabricated Panels

• Principle: A cavity of 30 - 50 centimeters is left between the foundation and the first-floor ground. The underground moisture will naturally dissipate after rising into the cavity and cannot reach the first-floor ground, thus achieving the purpose of preventing moisture.
• Specific Practice: After the ground beam is poured, control the height of the backfill soil at a position 30 - 50 centimeters away from the ground and compact the backfill soil to lay a foundation for subsequent waterproofing work.
• Measures to Improve Waterproof Performance:
  • Select High-Quality Prefabricated Panels: Choose prefabricated panels with good waterproof performance to enhance the waterproof ability from the material itself and reduce the possibility of moisture penetration.
  • Master the Correct Construction Method: Strengthen the bonding performance between the prefabricated panels and the frame structure and carry out construction in strict accordance with the lap requirements. Good bonding and standard lap joints can avoid gaps and prevent moisture from entering the room through these weak points.
  • Lay Waterproof Materials: Lay waterproof membranes or apply waterproof materials between the prefabricated panels to form an additional waterproof barrier and further prevent moisture penetration.
  • Pay Attention to the Ground and Drainage: Set the ground height and drainage reasonably to avoid water accumulation. If there is water accumulation on the ground, it may increase the risk of moisture rising and affect the waterproof effect.
  • Regular Inspection and Maintenance: Regularly inspect and maintain the bottom layer of the house with elevated prefabricated panels to detect and deal with water leakage problems in a timely manner. Once small leakage points are found, repair them promptly to prevent the problem from expanding.

Waterproofing for the Horizontal Joints at the Bottom of Prefabricated Exterior Walls

The construction method of “lower inside and higher outside” is adopted, that is, the joint opening on the indoor side is lower than that on the outdoor side, forming a “water-blocking step”. Even if a small amount of moisture enters the joint, it will flow to the lower side outdoors due to gravity and be effectively blocked outside the wall, preventing it from penetrating into the room and ensuring a dry indoor environment.