In Slovenia, primarily softwoods are used for construction purposes. They represent more than a third of wood stock in the Slovenian forests. It is expected that the share of softwood will decrease even more. So, we were interested if Paulownia wood could replace the spruce wood in building and construction applications; and if Paulownia is a good substitute for poplar and beech wood in plywood manufacturing. In addition, we wanted to confirm or reject the statements in promotional materials from providers of this respective wood claiming that the fast-growing Paulownia tree is more resistant to fungi than other comparable wood species, such as spruce and poplar. Besides, we were interested in mechanical properties of water exclusion efficacy and impregnability. Mechanical properties were performed in four wood species: Paulownia, poplar, beech, and spruce tree. Experiment was performed according to the American ASTMD1037-99 standard (compression) and European DIN EN 310 standard (bending strength). In order to determine durability, wood was exposed to four different types of fungi, namely Antrodia vaillantii, Gloeophyllum trabem, Trametes versicolor, and Pleurotus ostreatus for 12 weeks. For determination of impregnation, copper-ethanolamine product-Silvanolin and natural wax were used. The data showed that mechanical properties of Paulownia wood are not comparable to the spruce wood, therefore, Paulownia wood cannot replace spruce wood completely, since Paulownia does not have comparable mechanical characteristics. But this respective wood species exhibit much better performance against water and wood decay fungi.