When trees are cut for construction lumber, any of the wood that is to be used outside in the elements must be pressure treated. Without this special anti-corrosive treatment, wood will rot and will be consumed by insects and other animals.
How is Wood Pressure Treated?
To pressure treat wood, lumber is placed into a pressure tank and sealed. Air is then extracted from the wood in a vacuum process, and a chemical solution is added. This solution – made up of copper, chromium, and arsenic – penetrates deep into the wood under pressure in the tank. Each chemical performs its own duty in stopping decay. Copper is a fungicide, chromium is a bactericide, and arsenic is an insecticide. When treated properly, this process should keep wood safe from decay for many years.
Is It Possible for Wood Decking to Rot?
While the pressure treatment process generally works well, it is not effective 100% of the time. There are a few factors that could cause even fairly new pressure treated wood to rot. Let’s explore…
Defective Chemicals
There are occasions when the chemicals used in the treatment process are defective. Because each chemical performs a specific function, if one or more are defective, rot can begin to occur. Or, if the chemical cocktail was not properly mixed, the solution could also be defective.
Gauge Malfunctions
During the treatment process, wood is put under pressure so that the chemicals penetrate the wood completely. At the treatment plant, if a pressure gauge malfunctions, it is possible that the tank does not reach maximum pressure. If this happens, the wood may not fully absorb the chemicals.
Cracks Leading to the Inner Portions of Wood
It is not uncommon for pressure treated wood to develop cracks. In the construction process, holes must be drilled to attach the wood to its foundation. In warm weather wood expands, and in cold weather it contracts. This, along with foot traffic on decks, creates constant back-and-forth pressure on screws and nails. Over time, cracks can develop, allowing moisture to seep into the wood. If the chemicals deep within the wood are not present, or are scarcely present, this moisture can begin to rot the wood.
How Can I Tell if My Deck is Rotting?
Cracks and wood rot do not always go hand-in-hand. While you need to keep an eye on cracks, if the wood was properly treated, having cracks doesn’t always lead to rot. However, if you notice wood that is splintering, or is soft when you press on it, you might be experiencing rot. It is best to have a professional take a look and determine whether replacement is necessary.
What Do I Do if I See Rotting on My Deck?
If you do see signs of rot, it is recommended that the damaged wood be replaced as soon as possible. Chances are that it’s not your entire deck that is effected. Replacing the boards that do show signs of rot will help your deck last longer.
With proper care, your pressure treated wood deck should last between 10 and 30 years. However, this life span is only possible when conditions are not extreme, and when you clean and seal your deck regularly. Decks left unsealed will have a shorter life span.
