There are two main methods of applying preservative that are commonly used with fence panels and timber fence componentry – dip treated and pressure treated. Both of these applications are effective against water damage, insects and fungal decay but which should you choose for your project?
When choosing timber for a fencing project you may be confused by the variety of terms and types of treatment - you may have already read our articles on the difference between green and brown timber, and UC3 and UC4 timber.
What is dip treated timber?
- Dip treated timber has been immersed in a bath of preservative treatment then removed and left to dry
- The treatment may contain a brown dye to enhance the colour of the wood, but this doesn't have any extra preservative effect and will fade over time
- Because of the simple application, dip treated timber tends to be cheaper than pressure treated
- However, dip treatment only applies the wood preservative to the outside layer of the timber
- The timber will need to be re-treated annually after installation
What is pressure treated timber?
Pressure treated timber has been treated with a method that forces preservative deep into the wood with vacuum pressure
- The timber is loaded into an air-tight vessel and a vacuum is applied
- The vessel is then flooded with preservative at pressure while still under vacuum, forcing the treatment into the timber
- Excess preservative is then pumped out, the vacuum is released, and the returning air pulls the preservative even deeper inside the timber
- The treated wood is then allowed to air dry for 48 hours, resulting in a highly durable and water resistant timber
- Because the preservative treatment is forced deeper into the wood by the pressure treatment, the preservative effect will last up to 15 years
- However, the more complex method of application makes pressure treated wood more expensive than dip treated
Should I choose dip treated or pressure treated timber?
The main advantage of dip treated timber is its lower cost, and its 'instantly stained' appearance. However it will require regular retreatment and inevitably will not last as long as pressure treated timber.
Pressure treated timber is slightly more expensive, however this initial cost will be recouped over a period of time by less need for ongoing maintenance. In addition the uncoloured finish is preferred by many, providing a blank slate for your own choice of treatment.
Ask the experts
For further advice about your fencing project don’t hesitate to speak to our friendly and knowledgeable experts at your local AVS Fencing & Landscaping Supplies branch. Dip treated fencing and pressure treated fencing componentry is available from stock subject to availability, click and collect from your local AVS Branch or delivery within our AVS Branch delivery area.