During the history of civilizations, advanced wood decay results from exposure to various agents for long periods of time. Bio-deterioration, under the influence of living organisms like fungi, can cause massive damage to historical monuments. In this work, we found that fungi participating in wood degradation share a single strategy for degrading wood polymers by secreting enzymes that break down the main constituents of wood such as cellulose, hemicellulose and lignin. While Penicillium commune, Penicillium granulatum and Penicillium chrysogenum showed the highest cellulase productivity and are therefore the most destructive for timber, other fungal species participate also in this biodegradation including Penicillium crustosum, Penicillium expansum Cladosporium cladosporioides and a cellulotic specie Thielavia hyalocarpa that we describe here for the first time.