8 Different Types of Treated Wood and Their Applications

Treated wood -- and we're using this as a very general term here -- is a popular material in the construction industry because of its durability and resistance to rot, decay, insect damage, and even fire. However, not all treated wood is created equal, and choosing the right type of treated wood for a specific project can be critical. In this article, we'll discuss eight different types of treated wood and their applications.

1. ACQ Treated Wood: Alkaline Copper Quaternary (ACQ) treated wood is one of the most popular types of treated wood used in construction. It's made by impregnating the wood with copper and other preservatives that protect it from rot, decay, and insect damage. ACQ treated wood is known for its durability and is commonly used for treated lumber for outdoor applications such as decking, landscaping, and fencing.
2. CCA Treated Wood: Chromated Copper Arsenate (CCA) treated wood is another popular type of treated wood. It's made by using chromium, copper, and arsenic, which protect the wood from rot, decay, and insect damage. CCA treated wood is still considered by many construction professionals to be the best wood treatment option. It is ideal for outdoor projects that require a high level of durability and resistance to the elements. Due to regulations, CCA is only allowed for use in water, commercial projects, and specific residential applications. It's often used for wood bulkheads, structural applications such as retaining walls, and large timbers and poles.
3. MCA Treated Wood: Micronized Copper Azole (MCA) treated wood is a newer type of treated wood that has been gaining popularity in recent years. It's made by using micronized copper particles and other preservatives to treat the wood. MCA treated wood has a natural appearance and is highly resistant to decay, rot, and insect damage. It's often used for above-ground applications, such as decks and fencing.
4. CA Treated Wood: Copper Azole (CA) treated wood is another type of treated wood that's commonly used in construction. It's made by using copper and other preservatives to protect the wood from rot, decay, and insect damage. CA treated wood is ideal for outdoor applications such as decking, fencing, and landscaping.
5. Creosote Treated Wood: Creosote treated wood is a type of treated wood that's made by using creosote oil (a coal-based product) to treat the wood. It's highly durable and resistant to rot, decay, and insect damage, making it ideal for outdoor applications such as railroad ties and utility poles. It's use is much less common these days due to improvements in treatment technology. Creosote treated wood is also messy to work with and even causes skin irritation.
6. Borate Treated Wood: Borate treated wood is made by using borates, which are naturally occurring minerals that protect the wood from rot, decay, and insect damage. It's often used for interior applications such as framing, flooring, and paneling.
7. Fire-Retardant Treated Wood: Fire-retardant treated wood is made by using chemicals that slow down the spread of fire. It's often used in commercial and residential construction where fire safety is a concern. Fire-retardant treated wood is available in a variety of types, including lumber, plywood, and timber.
8. Modified Wood: Modified wood is a type of treated wood that has been modified at the molecular level to improve its durability and resistance to the elements. It's often used for high-end outdoor applications such as decking and landscaping.

These are just a handful of the types of treated wood available, each with its own unique properties and applications. Professional contractors and builders should carefully consider the specific needs of their project when selecting the type of treated wood to use. By understanding the different types of treated wood and their applications, contractors and builders can ensure that their projects are built to last.