During the service life of wooden floors ageing occurs, thereby altering their relevant properties, which can, however, be evaluated in a short time under simulated conditions of intense climatic loading. For this purpose, three groups of external wooden floors were exposed to artificial accelerated aging (UPS): only heat-treated specimens were included in group A, and in groups B and C the same objects were additionally protected with natural oil. During the standard process of cyclic loading with ultraviolet irradiation, infrared heating, and artificial rain the change of mass and moisture content, colour, dimensions and incidence of defects were determined on the specimens at intervals of 100 UPS cycles. The largest changes in mass, dimensions and colour were detected after the first 100 hours of loading. The changes in the A-specimens were absolutely greater than in groups B and C, which did not differ from each other. The first end cracks and surface cracks occurred in group A after 100 hours, and in groups B and C after 200 to 300 hours. We conclude that the signs of ageing in surface-oiled and heat-treated floorings were later and less pronounced than at the control A-specimens.
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