Pressure Treated Garden Timber

This covers some much needed clarity on our pressure treated garden timber.

Earlier this week we received a review on one of our products, part of it was:

“The first thing I noticed was how badly it had been pressure treated with green splatters on a number of pieces”

I personally really hate a bad review. this was one but unfounded. We try our hardest providing a top quality product with a top class service and will review everything requiring improvement where we can. Sometimes though it just comes down to understanding a product that you are buying and the expectations that match it.

This review has prompted me to write this quick post as from this statement it is clear that customers are not realising what tanalised timber actually is: I shall explain a little about it so people can gain more understanding of what you are buying and that there are no faults at all nor “badly” carried out.

Tanalisation / Pressure treatment are one of the same, it is the identical process and is carried out normally on pine timber for outside use as a rot protection:

Terms

The two terms used are describing exactly the same timber treatment:

• Tanalised is actually a trademark, as is ‘Tanalith E’ which you will see sometimes.  This brand has been around since the 1940’s.
• Pressure treatment is the process carried out using ‘Tanalith E’ or similar.

Process

The treatment process is carried out by placing the timber in a big tank.  The door is shut and a vacuum is created inside it.  Then the pressure treatment fluid is allowed to enter and is forced in the wood under the pressure.  It penetrates to a depth of a few millimeters.

Ingredients

The main ingredient is copper with other chemicals added.  Copper is excellent for protection against rot and insects.  The other chemicals (Biocides) protect against other rot that the copper can’t such as ‘brown rot fungi’.  These substances are not harmful at all and can be used around animals and children.  Fish may be sensitive to it.

Rot Proofing of Timber

It does exactly what it says and protects the timber from rot really well, internally they say about 60 years and externally about 30 years against any form of rot.  It’s pretty good stuff!

Promotional video explaining the Tanalisation process / Pressure Treatment

Limitations of tanalisation / Pressure Treatment

So now we understand how the process works, as the video explains, the timber will be:

• An initial light green colour.
• Weathers to a light honey brown.
• Eventually to a natural silver grey.

This change of colour is not any indication of loss of preservative protection. Subsequent decorative finishes can be added to create the look you desire, you will see many examples of this across our website and catalogue.

We supply fixings that will have a comparable life to the timber for many of our products but please note if timber is cut, notched, sawn etc then a comparable treatment will need to be applied to carry on protecting the timber.

Perceived Faults in Pressure Treated / Tanalised Timber

Occasionally, a customer will perceive faults in the process without a full understand of it such as the above review. Some of these perceived faults are:

Formation of salts:

With impregnated wood it may seem as if salts are formed on the surface of wood. It is actually resin that colours yellow/green due to the impregnation. These stains will vanish in time. This is an example and shows the ‘Splatters’ complained about in the review:

One of our fence panels displaying the formation of salts and “Splatters”

You can see from this picture green portions on the fence panel. We cannot help this as it’s part of the pressure treatment process. You may see this on your new pergola, planter or gazebo, please expect this, it is completely normal.

Fungi and blue moulds:

Blue mold and the formation of salt crystals.

Other faults

Light bleaching after the tanalisation process.