Several advanced non-destructive techniques are available to measure the evolution of content profiles with time, allowing the analysis of unsaturated flow and the determination of the moisture diffusivity of porous building materials. The reliability of six different techniques is investigated: the NMR-technique, the MRItechnique, the -ray attenuation technique, the capacitance method, the X-ray projection method and the TDR-technique. All of them were applied to measure the moisture content evolution during free uptake experiments on two building materials. Considering the limitations of some of the techniques, a good overall agreement is obtained. The work presented is an outcome of the EU-initiated HAMSTAD-project.