Mold spores cannot be seen with the human eye but they are present. Mold spores are the basis for mold reproduction. Mold spores exist in homes or buildings even with low humidity levels. It is sufficiently low humidity levels and/or a lack of cellulose based materials that prevent the growth of most mold species.
Mold will grow at 60% humidity and greater, or with water intrusion in the presence of degradable cellulose based materials such as wood and paper products.
Mycelial fragments (spore endoskeleton fragments) can cause allergic reactions. Some species of mold such as but not limited to Stachybotrys can cause serious health complications in people.
Primary Requirements For Mold Growth
Mold requires cellulose based material availability. Cellulose based materials have a carbon base and include but are not limited to wood, paper, cardboard, newspapers, upholstery fabric, wallpapers, glues, pressboard, veneers, etc. Mold also requires a water intrusion or high enough humidity level (typically 60% or greater but some molds can grow in much lower humidity levels), time (typically over 24-48 hours) and the presence of mold spores. Mold spores exist in the air and the normal flow of air in a building enters at a lower level (basement) and then rises and exists from a higher level (ex: ridge vents in attic). There are always spores in the air but in low humidity levels and in the absence of moisture they do not grow. Molds are a member of the fungi family. Fungi do not require sunlight to grow with species having varied growth requirements and appearance. Molds possess hyphae-branches not visible to the human eye. Spores grow on hyphae and are so light they can become airborne.
Common Types of Fungi
Some of the most common types of fungi are Cladosporium, Ascospores, Basidiospores, and Alternaria.
Cladosporium does not require much moisture and can grow on a wide range of materials. It can cause sneezing, fevers, and excess mucus production. This is the dark colored mold often found growing on the rubber edging seal on your refrigerator.
Ascospores and Basidiospores typically cause allergic reactions in people.
Alternaria Mold Alternaria mold is often found in kitchens and bathrooms around the faucets and sinks. It acts as an allergen.
Aspergillus, Penicillium, Stachybotrys, and Fusarium are molds commonly found in water damaged buildings. These molds require higher levels of moisture than the common indoor and outdoor molds, and they are linked to much more severe health effects.
This is a fairly common mold type. It is commonly found in buildings with leaking pipes, flood damage, foundation leaks, high moisture levels and more. Penicillium mold grows within 48-72 hours after a water intrusion. Aflavatoxin, a carcinogen, can be a byproduct of this mold’s growth cycle. It is also an allergen.
This is a fairly common mold type. It is commonly found in buildings with burst pipes, foundation leaks, high humidity levels and more. Aspergillus mold grows within 48-72 hours after a water intrusion.
This is the mold species that has received the most publicity regarding adverse health consequences. Stachybotrys atra.
Fusarium produces toxins called mycotoxins which can cause memory loss, headaches, fever, and even death. It requires high levels of moisture to grow. It is often found in the vicinity of standing water or regular water intrusions into a facility.
A risk assessment is the process of entering a building to ascertain the mold situation prior to remediation. It is the basis for setting up a mold remediation plan and includes a visual inspection, client interview, gathering a description of how the situation occurring, often taking photos, assessing who and how the location is normally used, assessing the basic state of the contents, and conducting pre-remediation testing with indoor and outdoor air sampling recommended and often taking physical samples.