There are basically three types of biological attack: attack by discolouring fungus, by destructive fungus and by wood-boring insects. Knowledge of these attackers and the conditions favouring such an attack is essential in order to prevent it by using the right system. If a biological attack has already happened, drastic curative methods must be employed.
Wood needs protection from a wide range of biological enemies. Particular climatic conditions can create fertile ground for bacteriological attack. This puts the wood at risk of fungal attack and it is important to differentiate between two different types of fungus: discolouring fungus and destructive fungus.
Discolouring fungus. This type of fungus does not damage the structure of the wood, it discolours it, creating unsightly patches. These only form when the level of damp is high and conifer wood is particularly susceptible to this form of attack. Mould and blue-stain fungus belong to this category. Mould can be removed with a suitable detergent and by sanding down, but care must be taken not to spread the spores in the environment, because they are allergenic and can be harmful to health. Blue-stain fungus penetrates deep into the wood and it is not possible to remove it completely by sanding down, thus running the risk of its subsequent recurrence. To prevent this fungus forming, action can be taken to reduce damp or by using protective systems tested according to the standard EN 152. Amonn offers Lignex Grund BPlv, Hydrogrund Plus, Aqualignex I as solutions to this problem.
Destructive fungus. Unfortunately destructive fungus is much more dangerous than blue-stain fungus and by the time it
appears it is usually too late. It feeds on the wood and as the mycelium invades the inside of the wood, it weakens its structure. The presence of such fungus is often only noticed when the fruiting body, the cap of the fungus, appears but by now the damage has already been done and the wood is at risk of losing its structural integrity. There are various types of this fungus: soft rot, brown rot, dry rot, wet rot and many more besides.
If an attack has been found, it is important to have its structural integrity checked by an expert so as not to run the risk of any buildings giving way with the attendant hazards. The areas attacked must be mechanically removed, not only where there is obvious damage but also a great deal of the surrounding area, to avoid remaining spores forming new fungus. The area removed must be replaced with new wood. This curative process is complex and unfortunately such intervention is not always timely. This means that any wood placed in climatic and operating conditions that may favour the formation of fungus must be provided with preventative protection using systems tested according to the standards EN 113 and/or EN 839. Amonn offers Lignex Grund BPlv, Hydrogrund Plus as solutions to this problem.
Wood-boring insects. Insects that feed on wood are well known, the most common being beetles and woodworm, but there are other wood-destroying insects such as termites, ants and wasps.
Some of these insects use wood as a nest in which to lay their eggs. Beetles are part of this group and it is important to know that during their life-cycle the larvae can survive in the wood for between two and six years, feeding on the lignin, the soft part of the wood, creating tunnels in the wood. The larva only transforms into the chrysalis from which the adult insect emerges at the end of this period leaving the wood full of the characteristic holes found in wood thus attacked. The presence of holes therefore indicates that the wood has already been compromised, making necessary a professional inspection to check its structural integrity.
In contrast, termites do not nest in the wood, they create a mound from which they emerge in a group to attack wooden structures, eating everything. There are three large categories of termite, the most dangerous being the subterranean varieties, coming from the soil. The best protection from termites is undoubtedly arranged at the time of construction and in areas particularly subject to insect attack, the use of suitable products can help prevent the problem.
In addition to protection at the time of construction, wood can be protected from termites using products tested according to the standards EN 117 and 118, while to protect the wood from such beetles and woodworm, products tested according to standard EN 46 should be used. For the latter Amonn offers the solutions Lignex Defend, Lignex Grund BPlv, Hydrogrund Plus Iv, Aqualignex I.
If curative action is required, when an infestation of beetle larvae has been found, a number of different measures can be taken and we advise against using do-it-yourself methods but to call in a specialist firm. After the structural state has been inspected, gas, infrared or other instruments can be used, or chemical products can be injected or introduced through the holes left by the emerging insects. In this case Amonn offers Lignex Defend, which not only eliminates the parasites as a curative function but avoids the problem reoccurring, thus performing a preventative function.
The Biocides Directive. In order to safeguard the health of people, animals and the environment, the EU has chosen to regulate the production and sale of biocidal products. The introduction to the Directive states that biocidal products are useful. We can no longer live in this world without making use of substances that combat certain parasites, you just have to think of their widespread use in agriculture and medicine. It is equally true that we must use only those active ingredients whose properties have been tested and we must seek to limit their use to situations in which they are absolutely essential. The Directive includes a list of substances that can be used. Products put on sale that comply with these regulations have been tested both in terms of their effectiveness and their impact on health and the environment.
It should be remembered that chemical protection for wood is only necessary when the wood selected and the measures taken at the time of construction have not been adequately planned to guarantee the wood’s protection from its enemies.