Basics of Exterior Wood Stain

Wood is a popular choice for outdoor structures around the yard and landscape. Wood is cheap, readily available and easy to work with. Ironically, once wood is cut from the tree, it needs to be protected from the elements of nature.

Exterior wood stain is used to protect wood from the damaging effects of the sun and rain. Applied to dry wood, exterior wood stain comes in a number of varieties that coat wood and preserve its natural beauty.

Bond, Wood Bond.
The two basic types of exterior wood stain are defined by how they bond to wood.

Film-forming exterior wood stain forms a protective layer over the surface of wood. These stains are durable and can create a high-gloss finish that will still allow the grain of the wood to show through. Film-forming exterior wood stain can be expensive, however, and will have to be stripped from the wood if re-staining is required.

Penetrating exterior wood stain seeps into the pores of the wood, extending protection beyond the surface. Penetrating exterior wood stain can be combined with pigment and preservatives to provide ultraviolet and mildew protection. Penetrating stains aren't available in glossy finishes.

Choose Oil Or Water: They Don't Mix
Exterior wood stains have different methods of adhering to wood.

Water-based stains are made up of tiny particles of pigment and resin that bond tightly to each other as the stain dries. Water-based exterior wood stains are easy to use and clean up, but often need more coats to provide the same level of protection as oil-based products.

Oil-based stains chemically fuse their particles to form a sheet-like coating that creates a harder finish that is less prone to yellowing. Oil-based exterior wood stain is generally more expensive, but provides a stronger, longer lasting finish.

Pick Your Transparency Level
Exterior wood stains come in a variety of transparency levels, from clear to solid colors:

• Clear stains will highlight the wood's color and grain, but offer little protection against the graying effects of sun damage.
• Semi-transparent stains can be used to highlight or change the color of wood and provides some ultraviolet protection for wood.
• Solid color stains extend the color range beyond natural wood tones and wear more slowly than other coatings. When solid stains do wear, however, they will expose the wood surface underneath.