It is often a common belief that the reason to preserve your exterior wood deck is to “seal” the wood so that it “beads” like a car wax. This is absolutely not true! This is a marketing ploy by the “Big Box” manufactures.
While it is helpful to prevent water damage, the main reason to treat your wood is for UV damage. If left untreated, the Sun’s ultraviolet rays will oxidize and damage the exposed layer of wood cells. When using a transparent tinted wood deck stain or sealer, the tint will act like “sunglasses” for your wood. The tint will absorb the UV and prolong the oxidation that turns the exposed wood cells gray. This is very important if you want to have your wood keep its natural color. The natural and/or synthetic oils in the deck stains will also replenish the wood that has dried out from the UV damage.
Depending on your conditions you can expect a high-quality deck stain or sealer to last 18-36 months on the horizontals and twice as long on the verticals. See Deck Stain for more info.
