How do I Choose the Best Deck Coating?

Whether a home owner is interested in protecting his deck from the elements or simply just looking to give it an appealing finish, deck coatings can provide the solution. Deck coatings vary in more than just color — they may also differ in function. It is important to choose a deck coating that specifically works with a home owner's deck, and takes into account the wood's degree of weathering, the need for a water repellent, and other factors.

In the past, home owners were encouraged to wait until about a year after a deck's installation before coating. The purpose behind was this to allow the deck to pass through the elements and "weather." As long as the deck hasn't had water repellent applied to it, however, coating a deck immediately after it's been installed is acceptable.

For those who have bought a house with a deck already installed, an easy test can be done to determine if the deck has been treated with water repellent. Home owners can simply apply water to the deck and observe the water's reaction on it. If the water is absorbed, the deck hasn't been treated with water repellent; water that stands, puddles, or rolls off signifies the presence of a water repellent treatment.

A deck's state of weathering may point to the appropriate deck coating choice. A deck coating that forms a film needs to be applied before any weathering occurs because weathering compromises the film's ability to bond with the wood, resulting in premature peeling. Penetrating finishes, like those that are oil-based and result in a semi-transparent stain, may afford a home owner more freedom during the application process. These finishes can be applied regardless of the deck's state of weathering.

It should be noted that many deck coatings are now considered to be film-forming. Paints, oil, water-based semitransparent stains, and latex-based solid-color stains are all categorized as film-forming finishes. In fact, even traditional, oil-based semitransparent stains have been reformulated enough to be considered film-forming finishes. In situations like these, reformulations of old mixtures contain higher solid ingredients due to environmental regulations. Thus, the new formulation loses its penetrative qualities and simply forms a film on top of the wood.

Generally, stains and film-forming finishes deter the sun's ultraviolet rays. For this reason, the deck coating will protect the deck from lignin destruction. As a result, decks with deck coatings will remain smoother and together longer.

A good deck coating will have a water repellent component. This slows the deck's water absorption rate but allows damp parts of the deck to dry as it normally would. Shrinking and swelling and subsequent splintering can be minimized if a water repellent component is chosen. Some deck coatings can also contain mildew deterrents.

Clear deck finishes should also be selected based on their UV resistance. UV resistance ingredients may include transparent iron oxides. Home owners should keep in mind that the longevity of clear finishes can vary. Some clear finishes may need to be reapplied every six months while others may only need to be applied every three years.