Deterioration of wood by climatic and air pollution effects

Mainly the deterioration of wood is connected to wood-water relations. Wood moisture will be related to the risk of decay of the wood by parasites. Often it is necessary to verificate the durability of a wooden construction. At the WKI a method is developed for testing the fitness of use by weathering simulation. The deterioration of wood takes place by attack of wood pests, specially fungal attack. Certain moisture ranges are necessary for the growth of fungi. To verify the safety of wooden constructions against fungal attack the moisture behaviour has to be estimated. There are different methods to estimate the moisture behaviour. Beside a standard, based on a simplified calculation method, fitness tests are to be carried out in test houses with natural weathering. Disadvantages of natural weathering like the long-term duration and missing reproducibility can be compensated by weathering simulation in double-climatic chambers. For each task, an appropriate simulation model has to be developed to simulate the impacts. During the last twenty years the WKI has been successful in investigating light structural elements as well as half-timbered walls made from solid wood using different types of simulation