What does "pressure-treated lumber" mean?

Pressure-treated lumber is lumber that has been treated with a preservative to protect it from fungi and insects for many years. To achieve this, the wood is placed in a closed horizontal cylinder Ð and then air is drawn out of the cylinder and out of the wood cells. The preservative is then introduced and the contents of the impregnation cylinder are put under pressure. In this way, the preservative is forced deep into the wood cells. After this, the vacuum is drawn back in to ensure that any excess preservative is completely removed. The process is followed by a fixing treatment to ensure that the preservative remains in the wood.

Why should wood be impregnated?

Wood is a renewable and natural material, which is constantly available, thanks to sustainable forest management. However, it is susceptible to attacks by fungi, microorganisms and insects. In particular, in contact with soil and water, wood is quickly affected and rots in most cases over time. Fungal attacks can also occur rapidly in other areas where the wood is exposed. There are only a few types of wood that, by their nature, are very resistant to rot and insect attacks. These types are mostly tropical woods and very expensive. Other types of wood must be protected before they are used - placed for a long time in permanent structures. By impregnating the wood a lifespan is given, many times longer than that of untreated wood, while the additional costs due to impregnation are low, especially when compared to the high maintenance and replacement costs of untreated wood.

How durable is wood, naturally?

The natural durability of wood depends largely on the type of wood, the density, the age of the tree from which the wood is cut and the conditions under which the wood is used. These factors are always variable, but impregnation of wood provides the certainty of long-term use in a wide range of applications. Unimpregnated wood is never stable.

How is wood impregnated with preservatives?

The impregnation industry has excellent techniques, with which the wood to be treated is impregnated using vacuum pressure cycles, to achieve the required absorption and depth of penetration.

After the impregnation is complete?

After the impregnation process is complete, the wood remains in the cylinder until the preservatives have set.

Can all types of wood be preserved by impregnation?

No. Due to biological differences between wood species, there are differences in the extent to which preservatives can penetrate the wood.

For example, the preservative does not penetrate more than a few millimeters into spruce, while the sapwood of pine is permeable to its core. In this case, the untreated sapwood becomes available to fungi.

Effectiveness of a wood preservative.

To be effective, a wood preservative must have the following properties:

  • toxicity against wood-destroying organisms
  • the ability to penetrate deeply into the wood
  • permanence in the treated wood
  • should not have any destructive effects on the wood itself
  • should be non-corrosive to metals
  • should not be harmful to health

All European countries have regulations and reliable procedures for the assessment of the above-mentioned properties. No approval is given for the impregnation preservative, in certified wood impregnation factories, until all relevant tests by the competent authorities have been satisfactorily completed. The European Biocidal Products Directive provides a global system for authorisations throughout the European Union.

Is treated wood safe for the environment?

Yes. Wood that has been treated in accordance with regulations and with officially approved preservatives does not pose a risk to humans, animals or plants. Researchers and government authorities are constantly searching for means and methods for treating wood products. The research covers everything, including the waste phase. All these studies confirm time and again that treated wood is safe for humans and the environment.

Where can I use impregnated timber?

Impregnated timber is used for:

  • electricity and telephone poles
  • sleepers, walkways and bridge timber
  • industrial cooling towers
  • marine docks and piers
  • embankments
  • for stakes (viticulture) and fences
  • playground equipment, gazebos and pergolas
  • decoration (wooden flower pots)
  • pavements
  • as construction timber

and for any purpose for which the timber is exposed to the effects of external weather conditions conditions.

Can children play safely on playground equipment made of impregnated wood?

Several studies have concluded that there is no risk to children playing on impregnated wooden playground equipment. There is no risk of the applied preservative being washed away, even by licking the wood.

Is impregnated wood safe for use in vegetable gardens and orchards?

Yes. Impregnated wood is ideal for low garden fences, for building compost bins, or as stakes for bean plants, etc. There is no risk of the wood impregnating ingredients damaging plants.

Is impregnated wood safe for humans?

As long as the wood is impregnated correctly (in accordance with European regulations), impregnated wood does not pose a risk to human health. For every purchase of impregnated wood, the consumer has every right to request a wood impregnation certificate.

Should impregnated wood be painted during construction?

No, this is not necessary because it is already impregnated to its core. However, there is also the aesthetic aspect. After a while, unpainted, impregnated wood changes color (gray shade) due to its exposure to external weather conditions. The speed at which this happens depends on the place where the wood is used. Our company offers varnishes with or without tint that impregnate the wood, are odorless and ecological. The only requirement is that the wood must be dry before painting.

No, this is not necessary because it is already impregnated to its core. However, there is also the aesthetic aspect. After a while, unpainted, impregnated wood changes color (gray shade) due to its exposure to external weather conditions. The speed at which this happens depends on the place where the wood is used. Our company suggests varnishes with or without tint that impregnate the wood, are odorless and ecological. The only requirement is that the wood must be dry before painting.

Is it possible for the impregnated coating to corrode?

The only, essentially, case in which impregnated wood can corrode is when strong chemicals, such as pesticides, fall on it. These substances greatly reduce the lifespan of the impregnated timber.

CYLINDER IMPREGNATION PROCESS

Impregnation is done using the full cell method (vacuum-pressure-vacuum).

  1. The timber is introduced into the impregnation cylinder and subjected to the initial vacuum. The air is removed from the pores of the wood, maintaining the vacuum.
  2. The vacuum cylinder is fed with wood preservative.
  3. Hydraulic pressure is applied, forcing the preservative to penetrate deep into the pores of the wood.
  4. The vacuum in the final stage causes the extraction of the preservative that was not absorbed by the wood and which is channeled back as a reserve.
  5. The wood remains in the cylinder, under air pressure, so that the preservative is absorbed into the heart of the wood.
  6. The treated timber is left to dry in atmospheric conditions.