Why does mold grow on silicone sealant

Building materials affected by mold

Which building materials are attacked by mold?

Mold on various building materials

Molds have a very complex and adaptable metabolism that allows them to use and colonize a wide variety of nutrient media and substrates. A thin layer of dust on a material can initially be sufficient as a breeding ground. The actual building material is only subsequently colonized or penetrated by the fungal network. There is an abundance of materials in building materials that can be colonized by mold. The basic requirement is always sufficient moisture in the settled material, since the molds, like all microorganisms, usually have a lower tolerance to drought.

However, there is also a wide range of fluctuation here. Some species are specially adapted to relatively dry substrates, whereas others can only colonize very moist nutrient media. This principle can also be found in the case of food spoilers, which usually only colonize one specific food or one food group. This circumstance restricts the range of species occurring in the event of a microbial infestation of the building structure, depending on the degree of moisture. There is also often a characteristic sequence of mold species, since after a one-off moisture damage, the slow drying of the building fabric also encourages other species or inhibits their growth. Thus, the species found can give an indication of how old a microbial damage is. In addition, it can be assessed whether the moisture damage is due to a single event or whether moisture is constantly seeping in.

A classic example is the occurrence of Chaetomium sp. on fresh structural damage with high moisture content e.g. B. after a pipe burst. Chaetomium sp. grow very quickly and expansively and can colonize the damp building material very quickly. Furthermore, representatives of the genus Cladosporium come into question in the event of fresh moisture damage, as they are most common in the outside air and are therefore usually the first types of fungus on site. In contrast, an occurrence of Aspergillus restrictus or Aspergillus penicilloides suggests an older infestation, which is already slowly drying out and only offers less moisture. These Aspergillus species can only establish themselves after a longer period of time, as they grow more slowly but tolerate less moisture.

For this reason, the identification of molds in the event of a microbial infestation, especially if it only occurs covertly, is of crucial importance. In this way, in addition to the pure physical measurement of moisture, the extent and duration of moisture damage can be estimated. This allows clues to be found as to how long the residents of an infested building were exposed to the mold. Furthermore, in the case of microbial damage in the interior, both noxious species and molds occur which "only" cause economic damage to the building. Both groups of mold cannot be tolerated in a building. But the schedule and the procedure for a remediation can depend on their occurrence.

The identification of the mold genera and species can only be carried out by specialists in the laboratory, since a considerable health risk for persons can arise without knowledge of the representatives of human pathogenicity and corresponding protective measures.

The following table gives a brief overview of which building materials can be colonized by different molds (according to Sedlbauer, 2001):