A systematic investigation of the hygrothermal properties of a number of oriented strand boards, plywood products, wood fibreboards and composite wood sidings has resulted in new information on the variations of thermal conductivity, water vapour permeability, moisture diffusivity, sorption- desorption-suction. isotherms, water absorption coefficient and air permeability of these classes of products in North America. The experimental and analytical procedures used in the investigation are all based either on International Standards or on well-documented and peer-reviewed approaches.

This paper presents the description of the products in each category and detailed information on the range of properties. The details include, density and temperature dependences of thermal conductivity, dependence of vapour resistance factor on relative humidity, dependence of moisture diffusivity on moisture concentration, equilibrium moisture content for the full range of relative humidity, variations in the water absorption coefficients and dependence of air permeability on pressure difference.