One of the most challenging things to paint are decks and fences. These challenges include getting the wood clean and dry enough to hold stain. The wood most decks and fences are built out of is some variety of cedar or pine. The soft wood does not lend itself to being pressure washed without a great deal of attention and care. Too much pressure and the wood fibers will expand and tear causing them to look “fuzzy”. Once this happens, it will be very difficult to get the wood to hold stain for any length of time. The three dimensional nature of most decks and fences make it difficult to clean them well. Poorly cleaned surfaces are the primary reason paint fails. For paint to stick, as the saying goes, the surface must be clean, dry, dull, and stable. These are just the beginning of the challenges your deck and fence wood faces.
You should be aware that your deck and fence are perfectly situated for failure. If you have a shady yard, the wood will be wet for prolonged periods after the overnight dew or a rainstorm. Moisture is a problem for most waterborne coatings especially on a vertical surface list a deck! The water will have the effect of softening the paint making it susceptible to scratching as your rearrange furniture across the surface or even by walking across the surface with a rock stuck in the treads of your shoe. Being in a sunny yard has even more challenges. UV rays are brutal on paint and stain. The intense heat and UV rays from the sun will take a huge toll on your coatings!
Once prepped appropriately, the proper material must be selected. If your deck or fence is made from cedar wood, you will have to ensure that you select a product designed to be compatible with the resins and tannins in cedar. If you apply a typical waterborne stain or paint to cedar the oils will cause it to release and peel off prematurely. There are many primers and stains designed for cedar application, but just be sure you’ve selected a product that is compatible. Most typical stains are made for pine as that is the most common scenario. Once the product is selected, now let’s talk application.
Stain should be applied to all exposed surfaces of the wood. Most fence and deck boards are too close together to apply the material to the edges of the board very well. Anywhere the material is not adequately applied will allow moisture to be absorbed into the wood and this will loosen the bond between the wood fibers and the coating. This process is exacerbated in the colder months when the surface dries much more slowly. Any water in the fiber that freeze will cause expansion and will cause disbonding even more quickly. As you can see, decks and fences are difficult to maintain! I would not expect more that five years of service from the coatings on my outdoor wood surfaces. You can greatly extend the life of these coatings by proper maintenance. Pressure wash your fences and deck every spring. I would apply another coat of stain to a deck every other year and to a fence every three years or so. You can reduce the issues with decks and fences by doing the job correctly to begin with, with frequent cleanings, and by applying one fresh coat often. This frequent coating ensures that any damaged coating is repaired so you keep the UV rays and water away from the wood. Stain is, after all, a sacrificial coating. The sun and weather degrades the stain instead of your wood!