An irreversible swelling was detected in laminated beech veneer lumber within the initial moistening. Supported by the facts that the lay-up of the glued veneers is exposed to high pressure during hot pressing, and that the density of the finished material exceeds that of solid beech, it was hypothesised that the wood substance is compressed. Laboratory X-ray density profile scans were performed to check this and to identify the part of the material cross section in which the densification has taken place. The higher density was found to be located in the area of the adhesive joints, uniformly over the cross section, while the density in the middle of the veneers corresponds to that of solid beech wood.