Impact of Thermal and Moisture Expansion on Design of Wooden Façade Elements for Retrofitting of Buildings

Building structures have been designed such that they are able to withstand the adverse effects of the environment for a certain time. The terms "for a certain time" and "the surrounding environment" are used for a purpose here, and that is because the phenomenon of ageing buildings is currently an increasingly discussed problem that is faced by every larger city. The materials used in the buildings, such as façade cladding, age just as the buildings themselves do. An immense pressure has been currently put on designers to use environmentally friendly materials not only for new buildings but also for the retrofitting of existing ones. The aim of this paper is to demonstrate that wood or wood composite materials are convenient solution for restoration of façades of administrative or commercial buildings, however, since the new cladding have to be connected with an old load-bearing structure, the designers have to overcome many limitations. One of the main difficulties is high thermal and moisture expansion of these materials which has a direct impact on the appearance of the façade. The obtained results showed that expansion properties should be studied closely when using wooden elements in the design and that a neglection can lead to a premature failure of the system.