- Wood is ordered and shipped to the treating plant from regionally sourced mills.
- Wood is checked for moisture content to ensure the moisture is not too high to accept the preservative treatment.
- Once the wood is unloaded, end tags are applied to every piece of lumber to denote the plant name and location, application and its abbreviation, the preservative name or its abbreviation, the retention level of the preservative retained in the wood indicated in pounds per cubic foot, and the trademark of the approved third-party inspection agency.
- The pressure-treating process starts when forklifts place the wood on a tram that will move the wood into a large steel cylinder; called a vacuum pressure vessel.
- Once the wood is loaded into the cylinder, the doors are closed, and the cylinder is sealed.
- An industrial vacuum pump removes air from the cylinder, and that includes pulling air out of the wood too.
- The cylinder is then flooded with the preservative solution.
- Pressure is applied to the solution in order to force the preservatives deep into the wood cells.
- Cycle times and pressure settings are adjusted based on the retention levels needed and the species of the wood being treated.
- Once the cycle has been completed, the cylinder is drained, then the industrial vacuum pump removes excess solution from the wood which is returned back to the work solution storage tank.
- A final vacuum is run within the cylinder to extract excess preservative which is returned back to the work solution storage tank.
- The door is opened, and the wood is removed. The freshly treated wood is then placed on a drip-pad for 24 to 48 hours.
- The wood is now ready for loading and shipping to building supply and distribution companies.
For some western wood species, incising is a common process where the wood is resistant to preservative penetration, but the preservative will penetrate along the grain. These wood species are prepared by creating small incisions into the wood prior to the pressure treating process. It is common practice to incise all sawed Douglas fir 3 inches or more in thickness before treatment.
Pressure-treated wood is the ideal choice for exterior building projects or projects requiring fire-retardant treated wood. Ideal for framing, decks, porches, railing, fencing, sheds, garden boxes, landscape walls, arbors, gazebos, swings, sandboxes and more; pressure-treated wood along with regular maintenance, gives your wood long-term protection to keep your project looking great.