Why Treatment Penetration Depth Matters in Pressure-Treated Wood Posts

Depth penetration in pressure treated wood is one of the most critical components for reliability, durability, and longevity when picking the right choice for your wooden fence post or trellis post. Not all wood posts are treated equally so understanding the importance of depth penetration is extremely valuable when investing in materials to complete your next project. 

What exactly is CCA Penetration Depth in Pressure-Treated Wood Posts? 

CCA Penetration Depth is how deep the chromated copper arsenate (wood preservative chemical) is pressure treated into the wood post. CCA is considered an in-ground contact chemical that prevents fungal decay, termites, and ​​deterioration on and within the wooden post. The greater the penetration depth, the longer the wood post will last, preventing premature decay. Penetration depth is limited to the sapwood, as the heartwood is naturally resistant and does not absorb treatment effectively.

Why is Shallow or Inadequate Penetration Depth a Problem? 

Shallow depth penetration, meaning the wood preservative chemical is not fully pressure treated within the wood post, and usually is only treated on the exterior layer of the wood. Some manufacturers and treatment facilities will only treat the outer layer of the wood and ends of the wood posts, also known as “turning the post green”, and is still considered treated to a certain CCA retention. Here is why shallow penetration on or within a wood post is a problem:

• Susceptible to Rot and Termite Infestation: Shallow penetration allows vulnerability to rot, decay, and termite infestation within the post.
• Decreased Lifespan: Improper penetration treatment can lead to premature decay of the wooden post within just 5-6 years, compared to properly treated posts that can last +25 years.  
• Diminished Durability: A post with weak core wood will deteriorate quickly, leading to post instability and structural collapse.

Deep Penetration Ensures Long-Lasting Performance and Protection 

Deep penetration that reaches the core of the wood, up to the heartwood of the post, ensures a wide range of comprehensive protection against:

• Premature decay, rot and moisture: Resists fungal growth and decay that erodes the wood 
• Termite infestation: CCA consists of copper, chromium, and arsenic which is lethal to termites and other wood-boring pests and has a repellent effect. 

How to Know if My Wood Fence Post or Trellis Post is Properly Pressure-Treated? 

Some good indicators and tips to know if a post is properly treated: 

• Cut open a sample: Cut the wood post in half and check for consistent treatment penetration beyond just the outer surface.
• Check for a Warranty: A good indicator of a properly deep pressure treated wood post, is strong warranty (e.g., 25+ years). 

West Branch Wood Treating Sales:
Manufactured for Long-Lasting Protection

We have experienced treaters and use an advanced treatment process that guarantees deep penetration throughout every post. We take samples by drilling 1 to 1.5 inches into the wood at approximately 20 different points. This thorough testing ensures our posts meet the highest industry standards for quality and treatment penetration. 

Unlike some competitors who only treat the external layers, our posts are pressure treated with industry-lead penetration depth for durability and longevity, creating a fence or trellis system that will last for decades!  

✔️ Backed by our 25-Year or 30-Year Limited Warranty – Guaranteed strength and longevity for each post 

✔️ Full-Depth Treatment – CCA protection inside and out 

✔️ Trusted by Farmers, Ranchers, & Fence Contractors Nationwide – A trusted choice for agricultural & farm fencing, deer fencing, solar field fencing, orchards, trellis systems, and more!

Invest in your next fencing, orchard, or vineyard project with West Branch Wood Treating Sales, a leading manufacturer of treated round wood fence posts and trellis posts. We ensure proper depth penetration in each post, leading to longer-lasting posts and high savings with fewer replacements. Set your wood posts once and forget about it for decades!