Pressure-treated lumber is any wood that has gone through a preservation process in which pressure is used in order to force the preservatives into the wood. The treated lumber will be placed into cylinders which are then closed, and pressure or a vacuum is applied to the wood.
The reason pressure is used in creating pressure-treated lumber is that a deeper and higher level of absorption of the preservative occurs in the wood.
Sometimes pressure-treated lumber undergoes several treatments, in order to ensure the deepest penetration of preservatives into the lumber. In the final step, a vacuum is used to remove excess preservatives.
When to use Pressure Treated Lumber
It is always advisable to use pressure-treated lumber in any exterior construction or in any situation where the wood might be exposed to moisture or humidity.
Pressure-treated wood resists water and is found in outside decks, ocean or freshwater piers, park benches, or any outdoor structure which has constant exposure to the elements. The preservatives in the treated lumber also are designed to resist insect infestation or fungal growth.
WARNING - EXTREME HEALTH RISK
Pressure-treated lumber gets its green hue from copper which acts as a preservative but the insects are prevented from damaging it by forcing arsenic into the wood as well. Arsenic can be absorbed through contact with human skin and build up in the body until it reaches a fatal or near-fatal level of toxicity. Remove any pressure-treated slivers immediately.