Working Under Pressure

Why Pressure-Treated Lumber Is The Right Choice

Pressure-treated wood has been around since the 1940s, but most consumers know very little about this popular and resilient fencing material.

Traditional wood fencing materials have long been the popular choice for agricultural fencing, especially on horse farms where its attractiveness, strength and visibility are highly prized for creating corrals, show rings and pastures.

Wood is a great building material: It’s strong, easy to work with, relatively inexpensive, and sustainable. The problem is, many varieties of bacteria, fungi and insects find untreated wood appetizing, decreasing the lifespan of wooden structures.

When untreated wood is in contact with the ground or moisture for any period of time, these organisms will significantly damage the wood within a couple of years.

Pressure-treated wood is manufactured specifically for outdoor use and will maintain its integrity in conditions that would cause untreated wood to rot. Structures like agricultural fences will last many years when constructed with pressure-treated lumber.


What Exactly Is Pressure-Treated Wood And How Is It Manufactured?

Pressure-treated lumber is wood (typically yellow pine) that has been immersed in a liquid preservative and placed in a pressure chamber. When the chamber is pressurized, the preservative is forced into the wood fibers. Using high pressure ensures the chemical reaches the core of each piece of wood—the process is much more effective than simply soaking the wood in the chemical or spraying it onto the surface.

The chemical preservatives are chosen to make the lumber very resistant to rot, decay and insect damage. In the early 2000’s, public concerns arose about the overall safety of Chromated Copper Arsenate (CCA), a common preservative used in the production of treated wood. In 2003, the EPA arranged a voluntary agreement with manufacturers of wood treatment chemicals to stop the use of CCA-treated lumber for most residential construction uses.

CCA-treated lumber is still allowed for use in permanent wood foundations, fence posts and boards, poles used as structural members on farms, marine construction, and lumber and timber for saltwater use.

Today, pressure-treated lumber is also treated with a range of chemicals in addition to CCA. These include Alkaline Copper Quaternary (ACQ), Copper Azole (CA), Sodium Borate (SBX), and Micronized Copper Quaternary (MCQ). These newer types of treated woods contain higher levels of copper, so they're much more corrosive than the old CCA-treated lumber.


Can I Treat My Own Wood?

NO! The American Lumber Standards Committee (ALSC) Treated Wood Program has accredited independent third-party agencies in the United States and Canada that regulate the pressure-treated wood industry. Monitoring of treating plant production takes place under standards written and maintained by the American Wood Protection Association and ALSC policies.

In addition to that, all treated wood chemicals are regulated by the United States Environmental Protection Agency (EPA) as pesticides, and all pesticides sold or distributed in the United States must be registered by the EPA.


How Can I Tell One Kind Of Treated Lumber From Another?

All pressure-treated wood has a green tinge and is heavy and wet when first processed. It can take several weeks for the lumber to completely dry, but the preservative remains in the lumber even after the water evaporates.

Pressure-treated lumber will have an end tag on each board or post to identify where it was treated; what chemical it was treated with; the chemical retention level (expressed in pounds of preservative per cubic foot; a higher number indicates more rot resistance); and whether it is rated for "Ground Contact" or "Above Ground Use" only.


Is Pressure-Treated Wood Safe For Use In Fences?

Yes. In 2003, the wood treatment industry voluntarily stopped using CCA for residential use due to concerns over the potential human health impact of arsenic leaching out of the wood. But CCA is so effective that it's still used in structures that humans infrequently contact, like telephone poles, agricultural fencing, and as understructure for docks.

All pressure-treated wood, regardless of the preservative used, is suitable only for outdoor use; it should never be used for indoor projects.


Tips For Working With Pressure-Treated Lumber:

Many DIYers might have questions about working safely with pressure-treated lumber. To reduce exposure and possible irritation, here are some simple precautions to take:

  • Wear gloves when handling treated wood and wash up thoroughly afterwards and before eating or drinking.
  • Always wear safety goggles and a dust mask when cutting, drilling, or sanding.
  • Cut treated wood outdoors, not in an enclosed space.
  • Never burn treated wood.
  • Allow treated wood to dry thoroughly before staining or sealing.
  • If you choose not to stain the wood, then apply clear wood preservative annually to maintain the wood's water resistance.
  • Before driving in a nail or screw, drill a pilot hole to prevent splitting the wood. This is especially important when fastening near the end of a board.
  • Over time, most treated lumber will shrink slightly across its width as it dries out. Take this small amount of shrinkage into account when laying fence boards.
  • After being outdoors for 6 to 12 months, treated lumber will develop cracks, called "checks," along the surface of each board. These hairline cracks are a normal part of the drying process.
  • The copper in wood preservatives corrodes aluminum, so fasteners such as nails, screws, and bolts used on treated wood need to be hot-dipped zinc-coated galvanized steel, stainless steel, silicon bronze or copper. Check the label on the fasteners to see if they will work with your treated wood.


Keep Pressure-Treated Wood Looking Good

You can stain or seal treated lumber once the wood is dry enough to accept the coating. To check if the surface of the wood is sufficiently dry, sprinkle a few drops of water onto the wood. If the droplets are absorbed, the treated wood is ready to be stained or sealed. If the water beads on the surface, you should wait a few days before attempting to apply a coating to the lumber.

One common misconception is that treated wood is more resistant to water, but that’s not true. Treated wood will soak up just as much water as non-treated wood. So it’s best to apply a waterproof coating. Wait until the wood feels dry on the exterior to apply.


Agricultural fencing impacts the day-to-day operations of farms—both positively and negatively. Effective fencing will improve farm management efficiencies and create a safe environment for corralled animals. Fences improperly designed or poorly maintained not only reflect badly on your operations, but they are also a hazard and a leading cause of injury to horses and livestock.

High quality pressure-treated fencing materials, properly installed and maintained, offer protection that’s unmatched by other kinds of wood, and will provide the strength and integrity an agricultural fence requires—and perform superbly for many years.

If it’s time for a new fence for your operation, take this opportunity to also consider design changes, upgrades and enhancements that will benefit your operations both today and for years to come.

There are many resources available that provide information for planning an agricultural fence, from online articles to county extension offices. Some fence installations can be do-it-yourself projects for those owners who have the time, skills and equipment. For larger projects or when DIY isn’t a practical option, fence contractors can get the job done for you. Plus, you will have the opportunity to add flair and personality to the project.

Contact us today! Meadow Ridge Supply can provide the top-of-the-line pressure-treated pine fence posts, slabs and boards you need to add the right fencing to your property.

Our expert wood fencing representatives can answer your questions and help you choose the right products to meet your needs.

Phone: 989-750-0750


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