The primary function of a wall system is to act as an environment separator, or in other words to keep the outside out and the inside in; this has not changed significantly over the past 50 years. The same cannot be said for the components and design of cavity wall systems, which have undergone a significant transformation in North America. Higher energy efficiency, more stringent fire safety requirements, sustainability, durability and better overall performance are driving design changes, and consequently a shift in requirement to satisfy codes and standards. At the same time there is also increasing demand from architects for greater flexibility in design to satisfy aesthetic goals. That affects what happens both inside the walls as well as on the visible exterior.
Non-open-joint cladding systems are no longer the de facto standard. They are intentionally sealed to limit the potential for water intrusion, but since walls will always get wet—whether through broken pipes, cracks, or moisture from air leakage—the lack of airflow through an improperly designed assembly can also contribute to numerous issues, including mold and rot of the materials. Open-joint systems, by contrast, are increasingly popular in North America. The gaps provide greater opportunity for water and air to get behind the cladding, but it’s that very air flow that improves the assembly’s drying ability. They also have the added benefit of giving architects the design flexibility they seek—varying textures and depth that come with selecting different materials and assemblies.