Wood is a natural, sustainable material. As such, when it’s continually exposed to environmental elements such as moisture, sunlight, and wind the physical attributes of the material changes and aesthetically evolves over time.
WHAT IS WEATHERING?
Weathering is defined as the chemical and physical changes that take place when timber is exposed to weather. Weathering factors that are responsible for the changes are: moisture (rain, snow, dew, and humidity), oxygen, solar radiation (ultra-violet (UV), visible, and infrared light), and temperature.1William C. Feist: Weathering and the Protection of Wood
It’s important to note that weathering should not be confused with rotted or decayed wood. Wood rot is a form of decay that results from a combination of fungi (microscopic organisms) and moisture. Wood must be consistently damp to foster fungi growth since fungi will not grow on dry wood. On the other hand, weathering is a surface phenomenon that typically only effects a small portion of the surface area. In the absence of decay, wood exposed to the weather can last many years since the performance and durability of the materials are not affected. As such, weathering should not be regarded as a problem, but rather a natural process that needs to be taken into account when planning for the preservation and protection of outdoor wood.