Rain screen solutions over components supporting element may lead to consider the outer layer and the cavity unnecessary. If this component is watertight, and taking into account that the joints between components must be sealed to grant airtightness, the inner layer can easily be enough to give the needed air and water tightness to the facade. The outer layer and the drained cavity make sense only when the inner layer material cannot support the effect of direct water. That is the case of wood –CLT or wooden boards-. On those cases the outer layer and the cavity stop direct water but cannot stop steam. An added steam barrier is needed to protect those materials.
