Influence of fungi on the state of preservation and on the usage prospects of antique wooden floor from manor houses in South-Eastern Poland

Floor structures are an integral part and a valuable element of antique buildings, and the only limitation of their preservation consists in their usage properties. A thorough study of their state of preservation is the starting point for choosing the correct conservation programmes. Currently, fungi are the main reason that leads to the replacement of antique wooden parquets in Poland. Simple visual inspections in many cases do not ensure a precise evaluation of the level of fungal infestation and the depth of penetration of the mycelium's hyphae in the wood. Tests of ergosterol, which is a component of most fungi's cell membrane, allow us to monitor the level of fungi infestation of diverse materials. This makes it possible to determine the depth of mycelium penetration within the wood quite precisely. Unfortunately, in case of basidiomycota it is not possible to correlate ergosterol with the mycelium's biomass nor with the grade of wood degradation. Moreover, tests of ergosterol are not able to answer the question whether the fungi infestation is active, because this substance is also present in dead fungi hyphae. The presence of ergosterol in the wood can only give us a hint of presence of a substrate mycelium, which is responsible for the secretion of exoenzymes that degrade structural substances. Therefore, only the test results of ergosterol content and of the wood's chemical composition, wettability curve and moisture equivalent, as well as computer simulations of its capacity to transfer gravitational and usage- related loads (on the basis of the elasticity modulus, bending strength and wood density) together with the hardness, resistance to abrasion and resistance to scratches of wooden parquets permit us to take a correct decision as to the possibility of their further usage. The research carried out shows that, in many cases, parquets infested with fungi can be used safely. The article presents the proprieties that are important in the correct assessment of antique wooden parquets' state of preservation and usage prospects. It specifies the factors that permit to eliminate the problem of fungi infestation and describes the proper usage conditions, proposing efficient methods of conservation. © (2013) Trans Tech Publicutions, Switzerland.