Currently, the appeal of a wood shake or wood shingle roof system principally is associated with its appearance. Other steep-slope roof coverings can imitate wood's textures, colors and shapes but rarely are mistaken for the genuine article.
Material property changes resulting from wood's interaction with the environment—referred to as "weathering"—are largely responsible for its aesthetic character. However, these same weathering effects provide indications of a wood roof system's physical condition. Early detection and appropriate response to certain conditions resulting from weathering can make a difference between a wood roof system's need for repair or complete replacement.
Weathering of wood
Wood degradation results from the cumulative effects of ultraviolet (UV) light, stresses from changing moisture content, leaching of natural wood preservatives and decay caused by fungi. The deterioration rate depends on roof slope, roof orientation, shading, climate, air circulation available for drying and wood quality.