What are the methods for preventing leakage and impermeability of dry hanging stone curtain walls?

1、 Reasons for water leakage in curtain walls

1. Three Elements of Curtain Wall Leakage

That is, pores, rainwater, and wind pressure. Therefore, the gaps and geometric shapes, dimensions, and exposure conditions of the stone board embedded in the structural body, as well as the size of rainwater, are important. The size of the pressure difference between the inside and outside of the curtain wall has a direct impact on the rainwater leakage function of the stone curtain wall.

2. Formation process of curtain wall leakage

When wind pressure and rainwater simultaneously act on the surface of the curtain wall. Rainwater splashes directly into the interior or flows down the curtain wall through the gaps on the curtain wall, and can seep into the interior under suitable conditions such as gravity, surface tension, or capillary phenomena.

2、 Specific measures for impermeability of curtain walls

1. Elimination of pressure difference opening method

The clever method is to install sealing strips in the gaps and holes on the outside of the curtain wall. Move the sealing treatment to the indoor side opening, that is, move the pressure difference to the indoor opening that is not in contact with rainwater. This ensures that there is no wind pressure in the area with water, and there is no water in the area with pressure difference, thus avoiding the possibility of rainwater leakage.

2. Sealing balance treatment method

The opening on the inner side of the opening chamber should be sealed. This is done to prevent high-speed airflow in the gaps, which can suck rainwater into the room. The height h of the inner flange of the crossbeam steel with the possibility of water accumulation can be increased to improve the waterproof and leakage products.

Multiple experiments have shown that the height h of the inner flange is basically close to the critical detection wind pressure value it is subjected to. Therefore, increasing the height h of the inner flange of the crossbeam is an effective way to improve the water tightness level.

3、 Open water diversion method

The villa stone curtain wall should be equipped with a unobstructed drainage channel system to quickly remove rainwater accumulated in the joints, which is very important for improving water tightness.

The main method is to arrange the drainage system reasonably. Generally, the embedded joints are arranged along the outer side, and the drainage holes should be evenly arranged with a spacing of about 500mm. The holes at the corners should be no less than 20mm from the edges, but the larger ones should not exceed 100mm.

To avoid water accumulation in the inlay groove, it is necessary to create certain pressure balance conditions. The horizontal distance between the drainage holes of the upper and lower crossbeams should be at least 50mm to prevent air flow and rainwater pressure from entering the room. Villa stone carving

4、 Implementation measures

Firstly, mark the leak location that has been detected, and determine the leak location of the curtain wall based on the size and flow direction of the water mark. The maintenance method is as follows:

1. Sealant construction

Firstly, determine the missing or missing adhesive area by visual inspection and manual testing, and then reinforce the area with adhesive patches.

2. Install sealing and water blocking lines

Adding a floating decorative line above the exterior wall can serve as a water barrier and prevent rainwater from seeping in.

3. Repair or replace damaged materials

4. After the weather resistant adhesive surface does not stick to the hands, conduct a water test experiment

Spray the completed construction surface with a 2cm diameter hose to determine if there is still water leakage.

5、 Specific construction method for weather resistant sealant

The weather resistant silicone sealant is bonded on both sides of the joint, and the sealing groove is filled with polyethylene foam strips to form a cavity inside the sealing groove. There is no sealing strip set in the outer gap hole, and sealing and gluing are carried out at the indoor side opening. The pressure difference is moved to the indoor opening that cannot be contacted with rainwater, so that the parts with water but no wind pressure and the parts with pressure difference have no water, which has an anti leakage effect.

The construction thickness of weatherproof seal shall be controlled within 3.5mm-4.5mm, because it is too thin to ensure the seal quality and prevent rainwater leakage, and it is also unfavorable to the tensile stress of steel due to thermal expansion, but it shall not be too thick. When the glue is too thick, the tensile stress is easy to be damaged, making the seal and anti leakage ineffective.