A modified cup-method for lightweight and highly permeable materials

With an increasing interest for dynamic hygrothermal calculation models for short time periods, there is a need for uncomplicated and reliable methods to determine the moisture properties for materials used in the indoor environment. The traditional cup-method is commonly used for building materials to determine the water vapor permeability. When used on lightweight and highly permeable materials, the unidentified inner surface resistance of the cup-method will be problematic and fastening the sample to the cup can be troublesome. To address these problems, we have developed a modified cup-method based on standard laboratory crimp cap vials to determine the water vapor resistance for lightweight and highly permeable materials, such as textiles and paper. This modified cup-method together with a validation is presented in the paper