General information about MSG19-3
The world of mold is colorful, but not healthy for humans. Photo: Pixabay
What is mold?
When we talk colloquially about mold we actually mean molds. This is a collective term for a large number of quite different microorganisms, but they all have in common that they initially form tiny fungal threads (hyphae) and in the further growth process so-called fungal spores. Since the threads are not only tiny, but also white, a mold infestation at the beginning of its formation with the naked eye is often hardly recognizable. It can only be seen on a white background when enough spores have already grown. These distribution organs are - depending on the type of fungus - for example, of black, green or brownish color.
Mold in the apartment. Photo: NicoLeHe / www.pixelio.de
However, with the reference to the many varieties of mold fungi, we have not yet explained exactly what is going on there when we see mold on the wall. The Federal Environment Agency points out in its above-mentioned guidebook namely that moldy surfaces often contain not only fungi, but also numerous bacteria. These microorganisms are once again significantly smaller than the fungi and therefore not visible. Unicellular fungi (yeasts) are also found frequently in the afflicted areas. Especially with older mold infestation often mites are added. These tiny arachnids feed on human dander, but also mold fungi.
Mold in the apartment. Photo: NicoLeHe / www.pixelio.de
Nutrients for mold
Many building materials consist mainly of mineral components and therefore do not provide a suitable livelihood for mold. This applies, for example, to concrete, sand-lime brick and bricks or cement, lime and gypsum plaster. Such materials do not contain any organic nutrients and thus actually do not provide a growth basis for microorganisms.
But only "actually". Even pure mineral interior surfaces are usually contaminated with organic substances. The normal house dust or the sticky soap film on the bathroom tiles usually contain fibers and pollen from the surrounding air or human secretion products such as hair and dander, which can serve as a food base for mold. In the current "Guidelines for the Prevention, Detection and Remediation of Mold Infection in Buildings", the Federal Environment Agency states in a nutshell: "As a rule, there are sufficient nutrients on surfaces in interiors".
Organic building materials
Building materials, which themselves consist of organic material, ie macromolecules based on carbon compounds, are of course particularly suitable for colonization by microorganisms. But here, too, is to differentiate. Paper wallpapers, materials made of plant fibers or plasterboard (with the cardboard as an organic component) are very easily attacked by mold in the presence of moisture. This also applies to plastics (construction films, silicone sealants, polystyrene), light wood materials or leather materials. By contrast, dense, solid solid wood products are less at risk.