Waterproofing of Prefabricated House Walls

Great attention should be paid to the waterproofing of joints in the exterior walls of prefabricated houses. Following the concept of 'diverting water is better than blocking it, and drainage is better than waterproofing', reasonable drainage paths are used to prevent water from penetrating indoors. The following are common waterproofing forms and key points:

Waterproofing of Precast Exterior Wall Panels with Internal Casting and External Hanging (PCF Panels)

This type of wall panel mainly adopts a joint waterproofing form that uses an external drainage cavity and sealant, with the interior relying on the self-waterproofing of the cast-in-place concrete. Its advantages lie in simple and fast construction. However, it is difficult to control the waterproofing quality, and cavity blockages often occur. Once the interior concrete cracks, it will directly lead to the failure of the wall panel's waterproofing. For example, during construction, if the drainage cavity is blocked by debris and rainwater cannot be discharged normally, it may accumulate in the cavity. When the pressure increases, the water will break through the interior concrete defense and enter the room.

Closed-line Waterproofing of Externally Hung Precast Exterior Wall Panels

This waterproofing form has three waterproofing measures. The outermost layer uses high-elasticity weather-resistant waterproof silicone, which can effectively resist the erosion of external rainwater. The middle part is a decompression space formed by a physical cavity, which can reduce the water pressure and the possibility of water penetration. The interior uses pre-embedded waterproof rubber strips in the concrete that are pressed tightly against each other up and down to achieve a waterproofing effect. At the cross joints between walls, an additional layer of polyurethane waterproofing is added outside the rubber waterstop. For rooms or buildings with particularly high waterproofing requirements, polyurethane waterproofing can be comprehensively applied on the interior side of the rubber waterstop to enhance waterproofing reliability. A drainage pipe is set on the exterior wall waterproofing silicone at intervals of about 3 floors to effectively guide the rainwater that has penetrated into the decompression space outdoors. This waterproofing structure uses three waterproofing layers inside and outside, combining diversion and blocking, and has a very good waterproofing effect. However, it requires extremely high construction precision, and any deviation in any link may affect the overall waterproofing performance.

Other Waterproofing Designs

The principle of the natural downward flow of water under gravity can also be utilized. The joints of the wall panels are designed into a rabbet shape with a higher interior and a lower exterior, combined with a certain decompression cavity design, to prevent water from flowing back into the room through capillary action. At the same time, rubber waterstops and multi-component weather-resistant waterproof adhesives are used to improve the entire waterproofing system of the prefabricated wall panels and further enhance the wall's waterproofing ability.