Mycological tests – In historic buildings exposed to the destructive effects of fungi, mold etc. organisms should be carried out thorough mycological studies. This is a special field of knowledge, therefore, these studies can be carried out only by scientific institutions with appropriate mycological laboratories (for example. Institute of Building Technology in Warsaw). Mycological studies should indicate not only the causes of destruction and reveal the nature of the biological threat, but they should also give guidance on how to proceed in combating this, extremely dangerous phenomenon for historic buildings. Attention should be paid here, that rooms in buildings without basements are most often exposed to biological attack, damp, poorly ventilated and without access to sunlight.