If a piece of timber is going to be outside, or in particular - in contact with the ground, it will need to be given a layer of protection to keep it safe from the elements and prolong it’s life and durability. This protection comes in the form of preservatives which can help prevent rot and repel insects. A common way of protecting timber is to have it pressure treated: a process which we will explain in this article.

Pressure treated timber is timber that has had chemicals forced deep into the wood. This process takes place inside a vacuum cylinder. When the wood is inside the vacuum it will have all air drawn from it to completely dry out the timber. The cylinder will then be flooded with the preservative at a high pressure to ensure it is forced deep into the wood. This process is completely computer guided. The wood is then left to dry before it is given a topcoat or used for manufacture.

The primary benefit to this process is the durability that is given to the wood. When used outdoors, the timber will be less susceptible to rot and moisture which can soften the wood. As a result it is also resistant to other parasites and keeps insects at bay. Pressure treated wood, with its resistant properties is therefore extremely durable and will last much longer than non-treated wood.

Due to the use of chemicals in this process it is generally advised that pressure treated wood is not used for areas in contact with food or children. As this is used as a protection against outdoor elements, there is no need for this sort of timber to be used inside the home.

However, if you are interested in an alternative to pressure treatment, there are a couple of options.

  • As mentioned before, some woods are naturally more resistant to rot than others such as Cedar or Redwood.
  • While pressure treatment will give the best lifespan, using a good enamel on the exterior of the timber and non-toxic heavy duty wood sealant will give good protection.
  • You can whitewash your timber with lime and water to create an exterior shell of protection.


At Haldane Fisher, we treat our timber at our Newry branch using either TANALITH (treated at high pressure) or VACSOL (treated at a lower pressure). Both of these brands are world leaders in timber treatment technology, allowing us to provide the highest quality product that has guaranteed long term protection against insects and rot.