The erection of new buildings, the renovation and preservation of building structures and monuments requires the quantification of the temperature, moisture, salt and pollution distribution in porous materials. The thermophysical modeling leads to a coupled nonlinear differential equation system. The temperature T and the capillary pressure p_cwill be used as driving potentials in this transport system. The air and salt transport and the crystallization and ice forming have been neglected in this paper although this processes have been formulated, too. In order to solve the transport equation system with modern numerical methods the material functions thermal conductivity λ(w( p_c),T ), capillary conductivity K(w( p_c),T ) and vapor conductivity δ(w( p_c), T ) and the moisture retention function w( p_c,T ) are necessary. This paper will be focused on the determination of w( p_c) and K(w( p_c)) in the isothermic case. The results will be compared with measurement results of the capillary active insulation material calciumsilicate.