Lets be realistic, most treated deck lumber rotting issues will occur to just about everyone sometime. Treated lumber contrary to the advertisements will not last forever even under the best conditions. However, the life of your deck or your fence can be extended if you follow some guidelines. Basically you need to keep the water from collecting and standing on the wood. If you can arrange to make sure that there is good drainage and avoid damp earth collecting on the wood, it will last a long time. let’s review a few examples to give you some idea. If you follow the basic rule, your deck etc will last many years.
Treated Deck Lumber Rotting – Guidelines
Since this post is about decks, we will discuss decks first. Always follow basic construction and design guidelines to ensure that you have a deck that is well supported. You want it to be strong enough to hold all possible weight conditions. Next ensure that the deck slopes slightly away from the house. All water and moisture will run off allowing the wood to dry properly after each rainfall.
Ensure that the bottom of all posts are above grade and that there is adequate drainage from around the bottom of the post. Any dampness that remains, will over time, cause the wood to soften and begin rotting. If your deck receives lots of shade, it may not last as long as on that is in full sun. It just will not dry out. Either relocate the deck or remove some of the trees to provide more sunlight.
Fence posts should follow the same rule. Either encase the fence post in concrete and cap above grade or encase in porous gravel to bleed away moisture. If the moisture sits there, it will cause the wood to rot after even a short amount of time. It will not matter if it is cedar or treated lumber.