Cold façades mount an envelope of air between the outer layer and the inner building shell. Air flows freely into and out of this cavity resulting in a sustainable, functional façade. The role of the cavity is triple:
- Eliminates pressure differences that would tend to blow water further in.
- Dries any moisture, such as rain that might be trickling down the back of the outer shield.
- Acts as an insulating barrier by minimizing thermal bridges and preventing heat buildup within the envelope.
Rain water and condensation are removed naturally by air flowing thought the cavity. The insulation material remains in good condition and effective over time. In a cold climate the air in the cavity circulates due to air pressure and thermal differentials over the height of the building. The condensation moisture at the rear of the cladding drys. In warm climate the moving air will cool the inner layers of the construction, and reduce the demand for cooling energy.
Facade height determines the size of the ventilation opening:
Height [m] Ventilation [cm]
0 – 5 20
5 – 10 50
10 – 20 70