Wood protection

Sustainable development includes also a wise use of wood and other renewable resources. As trees grow in forests, they sequester huge amounts of carbon dioxide from the atmosphere, helping to mitigate climate change. Proper basic protection of wood can significantly extend the life of our wooden products and buildings. In this way, we save on wood raw material and the costs of renovation, restoration and (re)production, while the carbon dioxide bound in wood is stored for a significantly longer period of time.

The field of wood preservatives (biocides) is becoming increasingly regulated in the EU. Over the last 15 years, a number of new regulations (e.g., Directive 98/8/EC on biocidal products, Regulation 528/2012 on the availability and use of biocidal products on the market, REACH – Regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals, etc.) have come into force, limiting the number of authorised active substances and their use.

The Office of the Republic of Slovenia for Chemicals (URSK) controls the field of wood preservatives in Slovenia. The impact of the authorised active substances on humans and the environment has been proven to be negligible, if the preservatives are properly selected and used. When using wood preservatives indoors, care must be taken to ensure that no harmful volatile substances are introduced into the wood, and when preserving wood intended for outdoor use, care must be taken to ensure that the active substances of the preservative are bound in the wood cell structure and are not leached out by precipitation. Leaching could contaminate the environment and reduce the effectiveness of the preservative itself. The manufacturer’s instructions should be followed thoroughly when using any product of this kind and the composition of the protective products should not be altered (by adding different substances or chemicals, diluting them, etc.).

At Silvaprodukt, we regularly strive to develop effective and as environmentally friendly wood preservatives as possible. All our products and methods ensure that wood protection complies with environmental guidelines and EU legislation. While we do not use any chemicals in the thermal modification of wood to permanently protect it against wood pests, all other wood preservatives are proven to ensure that the preservative components do not evaporate from the wood and are not released into the environment. Therefore, if the appropriate preservative is used, protected wood can be used indoors, in contact with soil and running water without any worries.

When choosing a wood preservative, we therefore need to make sure that it is effective (testing, compliance with standards), that it has the right formulation and that it complies with the EU legislation. When preparing major projects and project documentation, it is advisable to consult an expert in the field of wood protection (e.g., the Department of Wood Science and Technology of the Biotechnical Faculty in Ljubljana, Bureau Veritas, etc.).

The effectiveness of various oils commonly used in practice is highly questionable, as a surface application of oil alone over a long period of time cannot protect wood against wood-destroying fungi and other wood pests. Oils do not prevent the wood from becoming wetand thus from being colonised by wood-destroying fungi. The lifetime of wood protected with oils is therefore usually not significantly longer than that of untreated wood. Leaching of oils from the surface of also causes additional inconveniences: uneven appearance and staining of the surface, severe environmental pollution, and the need for frequent recoating. Often, the oils used in this way are also an excellent breeding ground for a variety of moulds that cause intense dark discolorations. Additionally, the surface of wood also becomes significantly darker due to applpication of oil, consequently causing more cracks on the surface due to more intense heatup form solar radiation.

The exception is creosote wood oil used to protect railway wooden sleepers. Creosote oil is a biocidal product which, due to its toxicity, is not available for free sale, its use is only allowed in specific cases such as railway sleepers. These are protected with creosote oil by vacuum-pressure processes, which means that wood completely impregnated bycreosote (and not only superficially). In addition, creosote oil is extremely harmful to humans and the environment, so wood treated with it should not be used in urban environments, gardens, etc. In the view of growing awareness and desire to protect the natural environment, considerable efforts and resources are being invested in research and development of new alternatives, that are more environmentally acceptable, among which the vacuum-pressure process for protecting wood with copper-based products and thermally modified wood are certainly promising.

To achieve excellent and, above all, much longer-lasting water repellency of wood surfaces exposed to the effects of the weather, we therefore recommend using Silvacera® wax instead of oils, which is natural, human- and environmentally-friendly, permanently bonded to the surface of the wood and is not leached easily. Silvacera® wax also does not darken the surface of the wood and, thanks to its water repellency, even reduces the possibility of cracks.