Directional drying is designed into high-performance buildings, and all three control layers must continuously manage water, air, and heat. Note how the air barrier is primarily accomplished at the interior and how difficult it is to prevent thermal bridging at structural framing if exterior rigid insulation is not used.
For children, the delicate, fern-like patterns left by Jack Frost on the inside of a windowpane can be magical. But for the owners of a brand new commercial building in the Midwestern U.S., they were more like a nightmare.
“There were 71 punched window openings, all of which had condensation on the inside that turned to frost in the winter,” explained a consulting architect who was hired to diagnose the problem and suggest a solution. “They tried lowering the interior relative humidity to get the condensation to stop. That didn’t work.”