Measurements of Water Vapour Permeability – Tightness of Fibreglass Cups and Different Sealants and Comparison of μ-value of Gypsum Plaster Boards

Values of water vapour resistance factor (μ-value) are one of crucial parameters for numerical modelling in building physics. To obtain a reliable μ-value is not so straight forward and requires good measurement equipment and skills. This paper at first briefly introduces a cup test which is commonly used method for evaluation of μ-values. Consequently a new test cups made out of fiberglass were tested regarding their vapour tightness as well as different sealant materials. Additionally the μ-values of three types of gypsum plasterboards were evaluated and data compared with values from other material databases. A good agreement of measured data was achieved.