Mold and Mildew at Home

Mold and mildew do not grow on dry surfaces. Mold and mildew are a natural part of our environment. Their spores can be found almost everywhere, including inside the house. Usually they are harmless. However, if the concentration of mold and mildew surpasses a certain level, it can lead to dangerous health conditions for the residents. In order to grow, mold and mildew require a lot of moisture.

The causes for increased moisture levels inside a building or home can include one or more of the following:

•  Cracks in masonry

•  Defective roofs, guttering, downpipes

•  Inadequate drying after construction

•  Entry of water as a result of broken pipes, floods, etc.

Inadequate removal of an increase in moisture or wetness from:

•  Improper heating and ventilation, especially in airtight buildings

•  Condensation (accumulation of condensation) in the area around “cold” walls, which resulting from, for example, thermal bridges in the external walls caused by inadequate or incorrect heating insulation and impermeation.

The list shows that, in addition to structural and building physics deficiencies, the residents of a building also contribute to an increase in moisture inside a building. Inadequate ventilation compounded by activities which create a lot of moisture (showering, cooking, laundry drying, running large aquariums, etc.) can cause an even greater increase in moisture. This will especially be a problem if the building is extensively sealed in order to reduce energy costs.

Mold and mildew can use a wide variety of materials as a culture medium/breeding ground, such as:

•  Carpets, adhesives for floorings

•  Diverse types of wood, face plates

•  Hangings or wallpaper (without special mold prevention)

•  Leather

•  Paints and lacquers (without special mold prevention)

•  Plastics, rubber, silicon (without special mold prevention)

•  Paper, cardboard, cartons (also plaster cartons).

Mold and mildew can even grow on cement and concrete. It can also grow on materials where there is no culture medium as long as there are sufficient organic particals and dust in the air, which settle onto the surface (i.e., glass surfaces).

Mold and mildew can only grow on materials if there is a certain minimum level of moisture. However, it is not the total moisture of the material that is decisive, rather only the moisture available to the mold and mildew. Mold and mildew can also grow on materials, which are not visibly moist. It is enough when there is a relative humidity of approximately 80% on the surface of the material. Espcially good growth conditions always occur when there is condensation on or in the material.

When mold and mildew infestation is discovered, the cause and source must be found. Only then should the infestation area be sanitized, whereby in any case, the cause and source must be attacked.

Protective measures when sanitizing, the formation of condensation:

•  Do not touch mold and mildew with bare hands – wear protective gloves

•  Do not breathe or inhale mold and mildew spores – wear protective breathing mask

•  Do not allow mold and mildew to come into contact with eyes – wear protective goggles

•  After completion of sanitation, shower and thoroughly wash clothes separately.

Source: Umweltbundesamt Fachgebiet II 2.3 (GERMANY), Innenraumhygiene / 2.4, Mikrobiologie