This paper presents results of experimental laboratory establishment of changes in physical properties (swelling, water absorption) of timber (spruce, pine, oak) caused by wood-destroying fungi (Serpula lacrymans, Stereum hirsutum). The experiment was carried out using standard test samples (20x20x30 mm) prepared from new timber and subsequently exposed to the wood-destroying fungi under optimal growth conditions for the period of 10 to 30 days. Changes in physical properties were observed in the damaged samples in compliance with CSN 490126 (equivalent to ISO 4859-1982, equivalent to ISO 4860-1982) and CSN 490104 Czech National Standards. The experiment proved changes in the observed properties depending on the wood and fungi species and the duration of the exposure.
