Timber structures and commodities are exposed to several mechanisms that limit their service life. The term service life refers to the duration until a limit state is reached, i.e. when the performance is no longer deemed acceptable.
Aesthetics is a branch of philosophy concerning studies on the nature and expression of beauty or taste. The aesthetics of a building is one of the principal aspects considered in architecture. Changes in the appearance of materials can differ due to kinetics of the responses related to the material resistance as well as due to intensity of the degrading factors.