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The Benefits, Types, and Applications of Treated Wood

Tips & Guides Timber Knowledge
01 January 0001 min read

When it comes to selecting the right type of wood for your woodworking or DIY project, treated wood stands out as a popular choice. Its durability and resistance to environmental factors make it a reliable material for a wide range of applications.


We explore the key benefits of treated wood, the different treatment types, and how this wood can be used effectively in projects.


What Is Treated Wood?

Treated wood refers to lumber that has been infused with chemical preservatives to help protect it from potential damage. The treatment process typically involves pressure-treating the wood with preservatives like chromium, copper, and arsenic. This forces the chemicals deep into the wood, helping to increase its longevity and weather resistance.


The Benefits of Treated Wood

Below are the main advantages of using treated timber:

  • Longer lifespan: Treatment protects against moisture, fungi, and pests, giving wood a longer service life. This makes it ideal for outdoor projects.

  • Reduced maintenance: The improved durability of treated wood reduces maintenance needs. Less checking, warping, and rot mean less upkeep.

  • Cost-efficiency: While the upfront cost of treating timber might be higher than untreated wood, its longevity and low maintenance needs make it a cost-effective choice in the long term.

  • Sustainability: Treatment extends timber's lifespan, reducing the need for replacements. This positively impacts the environment as it promotes sustainability.

  • Structural stability: Treatment protects load-bearing wood from insects and moisture damage, ensuring sound structural integrity.

  • Versatility: Treated wood can be used in exposed outdoor applications where regular wood would soon decay.


Types of Wood Treatment

There are three main wood treatments, which are the following:

Pressure Treatment

During timber pressure treatment, the wood is placed in a pressure cylinder and soaked with chemical preservatives. The pressure forces chemicals deep into the wood.


Common pressure treatment types include:

  • CCA treatment: CCA stands for chromated copper arsenate, a widely used preservative. It provides excellent protection against rot and insects.

  • ACQ treatment:  Alkaline copper quaternary contains copper rather than arsenic for enhanced safety. It protects against decay and termites.

  • Tanalith E treatment: Tanalised E utilises a water-based preservative with reduced environmental impact. Tanalised timber is effective against fungal and insect attack.

Surface Applications

Preservatives can also be brushed, sprayed, or dipped on the wood surface. This protects the outer layer but is less effective in protecting the interior wood than pressure methods. Common surface treatments include:

  • Borates: Borates are applied as a liquid solution which diffuses into wood cells, protecting against fungi and insects. It requires periodic reapplication.

  • Oils: Oils like creosote and linseed oil help repel water and provide limited protection from moisture damage.

  • Paints and stains: Pigmented finishes shield wood from UV damage while enhancing aesthetics and water resistance. However, these finishes require regular maintenance and recoating.

  • Fire retardants: Sprayed-on fire retardant chemicals can improve timber’s fire resistance, but their protection diminishes over time as weathering occurs. As a result, they require reapplication to remain effective.

Heat Treatment

The heat treatment process involves exposing wood to high temperatures, typically between 180 and 260°C, in a controlled environment for a certain period. This heat treatment alters the wood's chemical structure, reducing its moisture content and making it less appealing to insects and fungi.


While effective, heat treatments are energy-intensive and can compromise the wood’s strength,  so it’s crucial to consider the specific requirements of your project when choosing treated timber.


Key Applications of Treated Wood

Treated wood  brings its durability, moisture resistance, and longevity to a wide variety of exterior applications:

Structural Framing

Wood used in outdoor structural framing faces high exposure to rain, damp soil, and pests. Pressure-treated wood provides crucial protection for gazebo frames, porch posts, exterior structural walls, and load-bearing landscape structures. 


Components embedded in soil see constant moisture exposure. Treated timber holds up to fence posts, retaining wall sleepers, planter boxes, and raised garden beds. 


Pressure-treated decking endures foot traffic, spills, weather, and pests. It provides a slip-resistant, natural-looking, and budget-friendly deck surface. It's commonly used for deck floorboards, deck railings, and benches.


Public playground equipment faces heavy-duty usage from children coupled with outdoor exposure. This preservative treatment of timber makes it ideal for playsets, climbing structures, balance beams, and picnic tables.

Marine Applications

Wood constantly exposed to water faces a high risk of fungal rot and wood-boring critters. Pressure-treated timber is well-suited to docks, boardwalks, bridges, and boat construction. 


Bring Your Next Project to Life with Woodshop Direct

Treated timber offers clear advantages over regular lumber for wood projects where weather resistance, rot prevention, and longevity are critical. Sourcing wood treated with preservatives helps craft durable, sustainable outdoor structures requiring little maintenance.

When tackling your next outdoor woodworking project, be sure to check out the quality timber products offered by Woodshop Direct. Our wide selection of quality wood is complemented by our range of wood finishes and preservatives to protect and enhance your work. With expertise in woodcraft and a passion for sustainability, our team is the ideal partner for your next creation.