Water Vapor

Tolerable Moisture Content of Materials - ASHRAE 160

This presentation to the ASHRAE 160 hygrothermal modeling committee explains why it is important to protect OSB and other moisture-sensitive sheathing materials from excessive seasonal moisture content cycling. Building codes and current hygrothermal modeling criteria do not completely address this problem. Appropriate use of exterior continuous insulation in coordination with interior vapor retarders offer the “driest” solutions.