Protect your deck from the
elements.

Choosing a Finish

For a new deck built with pressure-treated lumber, let the decking dry out for about two to four weeks, depending on weather conditions. Test the lumber for dryness by sprinkling water on the surface. If it soaks in readily, the surface is ready to receive a finish. Untreated lumber should be finished as soon as it is dry to the touch. If you wait too long, the surface of the wood will have begun to degrade already.

Penetrating finishes soak into the wood to help prevent it from water damage and more. Types of penetrating finish include the following:

• Water repellents are transparent, protecting the wood from water damage without altering its natural coloration.
• Water repellents with an added preservative combat mildew. Ultraviolet (UV) stabilizers are additives used in some clear finishes that offer some protection from sun damage.
• Semitransparent stains are more durable than water repellents. The pigments used in the stain protect better against sun damage.
• Penetrating finishes can include an insecticide. Look for products specifically made for use on decks.

Film-forming finishes protect wood by creating a solid barrier (film) on the surface. This type of finish includes the following:

• Paint offers great protection against water and ultraviolet light, but virtually no protection against mildew. If you want to paint your deck to enhance its appearance, consider painting only the more visible, especially vertical, parts, such as posts and railings. Coat the wood first with a water repellent preservative and liberally prime the end grain before brushing on the paint.
• Solid-color stains weather quickly on horizontal surfaces and are difficult to repair once they fail.
• Lacquer and varnish do not hold up well under sun and rain.