Introduction

A rainscreen system is not a cladding material - it is a process where the substrate, waterproofing, structural support elements and cladding must be designed integrally to perform properly. It isn't just a panel screwed to a galvanized hat channel as many people espouse. In fact, it is much more sophisticated in its design approach, even when designing the connection between the panel and rivets for thermal movements (something often overlooked).

A rainscreen wall does not function properly unless the backup wall includes an effective air barrier, the wall cavity accommodates positive airflow and ventilation and the system is equipped with suitable drainage to evacuate moisture from the cavity. The ramifications of an improper design can be leaks in the exterior enclosure system that may require a partial or complete dismantling of the system to make corrections or repairs. A rainscreen system cannot be repaired by the application of sealant along breaches to the exterior face.

Alternately, the addition of wall cavities, vents and drains and air barriers, can significantly reduce heating and cooling energy losses, minimize condensation problems in summer and winter, minimize or eliminate the production of mold and reduce cladding maintenance to practically zero.

The rainscreen principle has been successfully applied to numerous types of cladding to include aluminum curtain walls, various precast wall systems, steel buildings, masonry walls and window designs. We feel that the application of the rainscreen principle offers the best overall rain penetration resistance in comparison to other methods.

This forum is a tool to educate and act as a clearing house for information on proper rainscreen design.