Hands on the controls
Before architects can even consider what the building will look like, they must ensure it will protect its inhabitants and maintain its integrity over the life of the structure.
The control layers of a building’s exterior are built to repel natural forces such as rain, wind, snow, ultraviolet (UV) rays, temperature changes, etc., in the long haul. These control layers include:
- A vapor retarder to minimize condensation by controlling the flow of water vapor as it shifts from high to low pressure areas.
- An air- and water-resistive barrier (AWB) which reduces energy and condensation loss by limiting the uncontrolled flow of air coming through the
wall assembly. - A water penetration barrier flashed to the cladding’s exterior to prevent water from entering the
wall cavity. - A thermal barrier to mitigate energy loss and prevent thermal bridging.
- A durable and water-shedding facade to protect against environmental elements, impacts, UV exposure, pollutants, and more.
The “pen test” can be applied to each control layer in the make-up of the exterior wall assembly. Each layer is assigned a color code; for each layer, one line should be drawn which follows the layer across the detail of the wall assembly. Any time the pen lifts from the page, it highlights a loss of continuity. Any breaks in the air and moisture barrier can promote unwanted airflow, compromise in comfort for the people occupying the building, cause potential damage to materials from unwanted moisture build-up, and decreased energy efficiency.
Smartly engineered building enclosure systems contain all control layers in an integrated, tested assembly. When the first four layers, which are not visible, are planned as an integrated solution beneath the surface of the cladding, the individual layers work together to deliver a holistic approach. When acting as an integrated system, these four layers can also accommodate multiple facade options.
Consider a building with concrete masonry units as a base, but the sheathing transitions to glass-mat gypsum or plywood sheathing on the upper levels. Specifiers can select a single fluid-applied AWB for these different substrates, and they are also effective under multiple types of cladding, such as stucco, cement board, wood, vinyl, brick, stone, and metal panels. While the consistency of the fluid application may need to be adjusted depending on the cladding above or below the substrate, a singular product as part of a tested system ensures greater reliability and less complexity. The fluid-applied AWB forms a bond with the wall sheathing and can act as a waterproof barrier when combined with joint and rough opening treatment.
