DAMAGES BASED ON FUNGI
Wood-destroying fungi are the main types of damage in wooden structures. The cause for this is always an excessive moisture content of the wood and its surrounding components. Wood damaging fungi is found everywhere with their spores in our ambient air. Once they find the ideal conditions they can colonize the wood and begin their destructive work.
In nature, the task of fungi is to convert dead wood into a biomass. So the cycle of nature repeats itself. This is not desired in buildings or other structures, leading to large damages and collapses in the worst case.
Different fungal species have different causes and the condition under which they grow. The individual species of fungi prefer different types of wood they infest and adapt their growth to their existing environmental conditions. Directly adjacent beams of the same species and the same age may have very different infestation. Under optimal conditions, the growth in a wood construction can increase by several meters a year. Adjacent beams can be infected.
Basically wood-destroying fungi can be divided into three categories. The late blight breaks down the cellulose in the wood and leaves residues of dark wood with diced break lines. The so-called white rot, breaks down the lignin and leaves bright cellulose fibers. The last category are blueness and slime molds, have no effect on the wood strength, but leaves a discolored wood surface.
The worst nightmare of all builders is dry rot (Serpula lacrimans). It is also the most dangerous of all wood fungi. It has the property to grow through walls, regardless of thickness of the brick masonry or concrete. This dry rot has the ability to penetrate a complete building from basement to roof and may spread to neighboring buildings. The danger of an improper restoration is that not all affected components are removed or treated and leaving the fungus in the dry state. The fungus can survive for a long time and after years when moisture is supplied fungal growth can start again. Dry rot requires mandatory reporting in some states and countries.
The species richness of wood-destroying fungi is diverse and cause damage to the building materials. It is necessary to identify the respective fungal species and the causes (increased humidity, and exposed working surfaces especially in the outdoor environment) to prevent further destruction.
Most major damage is already done when the fungus is visible. Wood-destroying fungi grow first in the interior of the wood where sufficient moisture is available and they are protected from the wind. In many cases, damage to the wood is visually recognizable, and can already lead to a statically relevant damage to the wood spreading to the apparently healthy sectional area beyond.
This damage can be determined using high-resolution electronic Resistograph ®drillings. A statement about the extent of infestation and a laboratory study of the fungal species can thus contribute significantly to a complete rehabilitation planning.