Wood stain is a type of paint that is used to color wood by soaking pigment into wood fibers with a solvent and then having it set and bind to the wood. Stain works by saturating color into the wood itself, rather than applying a layer of color over the surface of wood. The primary purpose of stain is to color wood, while offering certain protections as a result of the coloring and absorption of the stain deep into the wood. Perhaps the most common reason to use stain as protection is against ultraviolet light. Many stains help reflect UV light, which prevents wood surfaces from fading and losing their color.
What is wood stain?
Other ways stains protect wood
In addition to protection from the sun, stain can offer several other forms of protection to wood. For one, stained surfaces have color saturated within them so they tend to resist being further stained or discolored. Since stain soaks into wood and bonds with it, it doesn't allow other materials to soak in as readily, giving stained wood somewhat better resistance to water, and other liquid materials spilled on the surface. Certain types of stains can also contain ingredients that make for an inhospitable environment for insects, as well as the formation of molds and mildew.
Staining vs other wood treatments
While stain offers some protections for wood, other wood treatments can offer even greater protection. Since stain only soaks into wood, but does not create a protective barrier layer over the wood, the wood can still be susceptible to water damage, and invasion by insects, fungus and other organisms. Using standard paint is another way to color wood, which provides some surface protection, though it is susceptible to cracking and peeling which can allow water and malicious organisms to get into the wood. Varnish on the other hand creates a clear, hard barrier over wood, which provides excellent protection against water and other invasive threats.