Driving rain load
Exterior component joints are subject to the natural stress of driving rain. Here, raindrops are pressed against exterior wall components by wind pressure (up to 600 Pa corresponds to approx. 12 Beaufort) or as a result of air currents. The penetration of this moisture must be prevented, either structurally or by using suitable sealing products.
Sucking or capillary-forming joints in the building connection represent a further moisture load. Due to capillary action (narrow joint), water is drawn into the building structure without being affected by wind pressure.
For the external area of the building envelope, it is necessary to,
1. a defined drainage of moisture from the construction must be ensured.
2. the uncontrolled entry of water into the construction must be prevented.
3. limit the moisture content of sensitive materials.
4. a defined removal of moisture from the construction must be ensured.