What percentage of wood is considered decay resistant?

The concept of decay resistance in wood refers to a wood's ability to withstand fungal decay and degradation over time, particularly when exposed to moisture. When discussing percentages, it is generally accepted that wood species exhibiting decay resistance typically fall within a range based on their natural properties.

The threshold for a wood species to be classified as notably decay resistant is around 20%. This level indicates that the wood contains natural extractives and chemical compounds that provide some level of protection against decay organisms. While certain species may be more or less resistant, the 20% benchmark serves as a standard in understanding which woods may be more suitable for outdoor applications or environments prone to moisture and decay.

Other options reflect higher percentages, which would imply a much stronger level of resistance than is commonly recognized within the industry. Understanding this helps in selecting appropriate materials for construction, preservation, and sustainability within architectural practices.