Moisture Diffusivity of Building Materials from Water Absorption Measurements

Moisture diffusivity is a transport property that is frequently used in the hygrothermal analysis of building envelope components. This property is de pendent on the local moisture content. The experiments that lead to the detailed in formation on the dependence of diffusivity on moisture content are often very so phisticated. However, two recent exercises, as a part of the activities of an International Energy Agency Annex, have shown that a correct estimate of the mag nitude of the moisture diffusivity can provide useful information with regard to its application in hygrothermal analysis. This technical note presents results from a sim ple moisture absorption measurement that led to a good estimate of the moisture diffusivity of building materials. Results from measurements on a sample of spruce are presented.