Wood deck treatments come in four basic types. Clear water-repellent sealers are popular because they allow the natural grain and color of the wood to shine through. However, the transparency of the sealer doesn't do the best job of protecting the wood from UV radiation. This type of water repellent sealer may last only six months before the deck begins to weather again. UV radiation penetrates the top 1/64th surface of the wood, breaking down the composition of the wood.
The second type of wood deck treatment is also in the water repellent sealer category. However, this type of sealer will have some tinting. This tinting will often assist in restoring the wood to more of its natural color, and the addition of the tinting and toner increases the UV protection, which will extend the length of time the sealer remains viable. "Consumer Reports" says that clear and semi-clear water-repellent sealers are the least effective treatment products for wood deck preservation.
The third type of treatment is also semi-transparent, but these are often identified as stains. They will have more color than the basic water sealer. This is particularly good if you are re-staining a deck. In this case, choose a stain that is similar to the earlier stain but somewhat darker in tone. For a stain to penetrate the wood surface, any preexisting finish must be removed or worn off. This finish will often last up to three years before it needs to be redone.
The fourth and best type of wood treatment is an alkyd finish stain, which cleans up with solvent. This finish is opaque, and most of the wood grain will be covered in much the same way that paint covers wood. "Consumer Reports" placed the Cabot Decking Stain 1480 as the top-rated wood deck treatment for overall performance.
All wood deck treatments will improve and extend the life of your deck. Changes in environmental laws have removed certain wood decking products from the market, so it is important to examine older decks to see what materials were used to build it. If you are uncertain if you should replace your deck, ask your local building inspector or an expert from a lumber store to examine your deck and make recommendations.