Wood Preservation 101: The Chemicals We Use
- Old South Wood Preserving, LLC
- Dec 30, 2025
- 2 min read
How We Preserve
Behind every long-lasting post, beam, and board is a carefully controlled preservation process designed to protect wood from the elements.
Our treatment process begins by placing Southern Yellow Pine lumber into sealed, airtight cylinders. These cylinders are then filled with pressurized water and a precisely measured preservative solution. Under pressure, the treatment penetrates deep into the wood fibers, creating long-term protection against decay and insects.
Once the treatment cycle is complete, the lumber is removed and transferred to a contained drip pad, where it is allowed to dry thoroughly. This step ensures excess solution is captured responsibly while the wood stabilizes. After drying, the finished products are prepared for shipment to our customers.
We treat our lumber using two proven preservation systems: Chromated Copper Arsenate (CCA) and Micronized Copper Azole (MCA), each selected based on the intended use of the wood.
Get a behind-the-scenes look at our treating process in the video below.
Chromated Copper Arsenate
Chromated Copper Arsenate (CCA) pressure-treated wood is a time-tested solution for industrial and heavy-duty applications. It provides powerful protection against fungal decay and termites, making it ideal for environments where durability is critical.
CCA-treated wood products are clean, odorless, and non-staining, offering an economical and reliable choice for commercial and industrial construction. For decades, CCA-treated materials have proven their performance in some of the toughest conditions.
CCA Retention Rates
We offer CCA-treated lumber in three retention levels to match specific application requirements:
CCA .40 – Commonly used for ground-contact applications such as fence posts.
CCA .60 – Suitable for ground or freshwater contact, often used for larger structural components like 6×6 timbers.
CCA .80 – Our highest retention level, engineered for marine environments, including boat docks and waterfront structures.
Micronized Copper Azole
Micronized Copper Azole (MCA) is a modern, copper-based wood preservative designed primarily for residential applications. It is used in pressure-treated lumber intended for above-ground, in-ground, and freshwater contact projects.
Like CCA, MCA delivers dependable protection against termites and decay, while being well-suited for decks, landscaping, and structural components around homes.
MCA Retention Rates
Our MCA-treated lumber is available in two retention levels:
MCA .06 – Designed for exterior above-ground applications such as decking, railings, and framing.
MCA .15 – Intended for ground-contact applications, including structural posts, landscaping timbers, and any wood in direct contact with soil.
Quality You Can Count On
We stand firmly behind the quality of our pressure-treated lumber, which is why Old South Wood Preserving, LLC proudly offers a 30-Year Warranty on our products. This warranty covers damage caused by fungal decay or termite infestation that would render the wood structurally unfit for its intended use. It applies to both Above Ground and Ground Contact treated framing members that are critical to the safety and performance of a structure, including joints and beams. Simply put, our preservation process isn’t just designed to meet expectations; it’s built to last for decades.
