The X-ray examination method using computed tomography is widely used in the wood industry. Due to the need to replace tomographs and how they work, it is still a stationary method. It is difficult to use a mobile in the field, but using it with individual structural elements or their fragments is possible. X-ray computed tomography tests were carried out at the Warsaw University of Life Sciences. A Nueusoft medical X-ray computed tomography was used. The tomograph settings were optimized based on previous timber studies. Twenty-four construction fragments from barracks of the German Nazi camp KL Lublin were used for the study. The camp was established during World War II and operated from 1942 to 1944, and was a site of mass extermination. The main advantage of such tomographic examination of historic objects is the ability to non-invasively learn about the behaviour of the internal structure of wooden structural elements. Thanks to the spread of portable devices, in the future, it will be possible to perform in situ X-rays without the need to transport monuments. However, these are still usually devices adapted to examining movable monuments rather than buildings. Investigations of barrack construction fragments using X-ray computed tomography allowed a precise determination of the timber's density and the identification of degradation processes within parts consisting of several elements. Field observations regarding the low number of insects feeding sites in the structural elements were also confirmed. The results from the X-ray image analyses were also used in subsequent building inspections.