I receive a lot of questions on the subject of how to protect a wood deck. I wrote earlier about UV and water, the two deadliest enemies of wood. Whether a hardwood or softwood, natural or pressure treated the fibers need protection. I am not going to recommend any one treatment, there are too many out there and they have different objectives. I thought I would discuss the factors to consider.
Climate- hot and dry, humid, cold, extremes of both? Seasonality plays a big effect on wood, particularly absorbing moisture in the winter, and then suffering hot dry summers. The constant humidity changes can cause the fiber to split and warp as it dries too quickly and then has to reabsorb moisture later.
Every species reacts differently to the elements, some of the pressure treated woods need to have frequent treatments, particularly in the southern climates. Cedar is a very stable wood and will not shrink or warp to the same extent as the pines or firs. The hardwoods can be very dense, and will not absorb treatments as readily as the softwoods so make sure you consider this when buying sealers. Sealers work best when absorbed into the fibers, not creating a film coating on the surface. There are sealers on the market that do consider the nature of the wood decking.
New decks should be protected as soon as you can, any wood left exposed to the sun will start to degrade quickly and turn gray. This will affect how the sealers will work as well. Before applying sealer make sure the deck is clean of any dirt or mildew, a good cleaner and a “gentle” pressure washer/garden hose will do the trick.
Picking the right sealer is difficult, there are numerous brands and the key components must be a UV protector and a water repellent. but by category the listings can be condensed to clear, semi-transparent or solid. Do you wish the natural color of the wood to show or is the deck an older deck that already is gray or previously stained, this is where a color additive will make that old deck look newer.
A lot of choices and factors to consider but bottom line, sealers and stains will add life to your deck, enhance the appearance of the deck and add value to the house.