Make sure to choose a deck stain or sealer that will repel water, resist mildew, and prevent fading in high traffic areas. Sealers and stains are either water-based or oil based. Oil-based finishes tend to hold their color a bit longer, but water-based finishes tend to be more durable and last longer.There are four major categories of sealants and stains, listed in order below. Each contains increasing amounts of pigment.The more pigment you apply, the less wood grain and texture are visible, but the better protection you are providing for your wood.Clear water repellant often provides basic protection, including waterproofing, minimal UV protection, and sometime mildew growth prevention. Because these are clear or natural-look finishes, there is minimal amount of UV protection and the underlying wood will begin to gray within a few months. Performance ranges from 6 months to up to 2 years.Toner or Tinted water repellant is very similar to a clear sealant, except additional pigment or color is added. This provides additional protection against sun damage, further delaying the graying of the wood. In addition, the color can help to restore the original look of the wood even if a small amount of fading has occurred.Semi-transparent stains contain additional pigment, providing subtle color while still showing the grain and texture of wood. These provide additional protection against water and sun damage, usually lasting for three or four years. When choosing a stain, remember that the finished color varies based on the wood itself. If you are applying a new stain over an old one, choose a color that is similar to or darker than the original. To allow the new coating to penetrate into the wood, the old coating should be adequately worn or thoroughly stripped. Try a small test-patch of the stain in an inconspicuous area to ensure the proper color and appearance.Redwood and cedar contain naturally occurring pigments called tannins that may bleed to the surface. On these woods, either use a dark-colored stain that helps to hide the tannin or use a wood cleaner that is specifically formulated to remove tannin stains. To maintain a fresh look, recoating may be done every two to three years.Solid stain provides the most amount of pigment or color, and therefore the best protection for wood. However, it also hides the wood grain, only allowing some of the texture of wood to show through. Because of the excellent hiding properties, solid color stain is often used for heavily weathered wood, covering up damaged wood fibers. There are often more color choices with this category, so an attractive alternative would be to select complimentary colors for the horizontal boards or railings and the vertical balusters or spindles. Performance is often 5 years or more, depending on the level of direct exposure to sun and weather, and the amount of foot traffic encountered.
