Application of large sets of experimental data containing measurement errors in computational analyses without any preprocessing can lead to distortion of results. Therefore, transformation of these data from point-wise given values to smooth curves is one of the key factors allowing their proper utilization. In this paper, determination of moisture diffusivity of autoclaved aerated concrete as a function of moisture content using measured moisture profiles, which are processed by smoothing, is presented. For the processing of experimentally measured data smoothing splines are used.