Timber is a versatile and widely used material in construction projects, outdoor structures, fencing, and much more. However, not all timber is created equal, especially when it comes to treated wood. Two common types of treated timber you might come across are green treated and brown treated timber. While they may seem similar at first glance, they have distinct characteristics and uses. This blog post will explore the differences between green treated and brown treated timber, helping you make an informed choice for your next project.

What Is Treated Timber?

Before we dive into the specifics of green and brown treated timber, it's essential to understand what treated timber is. Treated timber refers to wood that has been treated with chemical preservatives to protect it from natural decay, insects, and weathering. This treatment extends the timber's lifespan, making it suitable for outdoor use and in environments prone to moisture and pests.

Green Treated Timber

Green treated timber gets its name from the slight green tint the wood adopts after treatment. The green colour is a result of the copper-based preservative used in the treatment process. This preservative, known as Copper Azole, Copper Chrome Arsenate (CCA), or Alkaline Copper Quaternary (ACQ), is designed to protect the wood against fungi, termites, and other wood-boring insects.

Characteristics and Uses of Green Treated Timber

  • Durability: The chemical treatment makes green treated timber highly durable and resistant to rot and insect damage.
  • Appearance: The distinctive green tint fades over time to a more natural wood colour, although it may still retain a slight greenish hue.
  • Applications: Ideal for structures directly in contact with the ground or exposed to the elements, such as decking supports, garden beds, and fencing posts.

Brown Treated Timber

Brown treated timber is similar to green treated timber in terms of its protection against decay and insects. The main difference lies in the colour, which is achieved by adding a brown dye to the preservative solution. This results in timber that has a more appealing aesthetic from the get-go, often preferred for visible structures where appearance is key.

Characteristics and Uses of Brown Treated Timber

  • Aesthetics: The brown dye added during the treatment process gives the timber a warmer, more natural appearance that blends well with outdoor environments.
  • Protection: Like green treated timber, brown treated wood is resistant to fungi, termites, and other pests.
  • Applications: Often used for decking, fencing, and outdoor furniture, where the appearance of the wood is as important as its durability.

Choosing Between Green and Brown Treated Timber

When deciding between green and brown treated timber, consider the following factors:

  • Aesthetics: If the visual aspect of the timber is important for your project, brown treated timber may be the better choice.
  • Environment: Both types of treated timber are suitable for outdoor use, but you may prefer one over the other based on the specific conditions and climate of your area.
  • Cost: There may be a cost difference between green and brown treated timber, depending on your supplier and the availability in your region.


Both green and brown treated timber offer excellent protection against the elements, decay, and pests, making them great choices for various outdoor projects. The main differences lie in their appearance and how they fit into your project's aesthetic goals. Understanding these differences allows you to select the most appropriate type of treated timber for your needs, ensuring durability and satisfaction with your outdoor constructions.