The moisture/thermal performance of an insulated residential wood-frame wall structure was investigated. The study included the effects of three types of vapor retarder systems, and the effects of zero, positive and negative total pressure differences across the wall. Exposure was representative of a Northern winter climate.

The primary objective of this investigation was to study the migration and accumulation of water vapor and its effect on the thermal performance of a typical insulated wood framed residential wall structure, under various conditions of vapor retarder (barrier) and total pressure differential.