Moisture Storage and Non-Isothermal Transport Properties of Common Building Materials

Equilibrium moisture content data are presented as a function of relative humidity for common building materials: plywood, oriented strand board, vinyl covered gypsum board, plain gypsum board, extruded polystyrene insulation, and insulation board. The measurements were made using a new technique where the samples are suspended inside a chamber containing saturated salt-in-water solutions that maintained various relative humidity levels ranging from 11.3% to 97.6% while at a constant temperature of 21°C (70°F). Isothermal and non-isothermal moisture flux data for oriented strand board and extruded polystyrene insulation are also provided. Isothermal measurements carried out at 24°C (75°F) and 7°C (45°F) indicated that the average temperature does not significantly affect the permeability for the materials. The moisture permeability is given as a function of average relative humidity for each material. The measured moisture flux under isothermal and non-isothermal conditions is compared to the theoretical ...