Question: In my basement in the corner wall we have a large amount of green and black mold growing. It has been raining a lot lately and has been very damp. We have a finished basement, chip rock painted and the mold is growing on that. Can you tell the type of mold by the color? Is this a real bad thing? Is the mold growing in the walls or just on the out side? What should be done to fix this problem?
Answer: It’s difficult to identify mold on color alone especially when growing on say a drywall. A number of molds look alike and the only way to differentiate them is to examine them under a microscope. However, an experienced mycologist (one who studies molds and yeasts) can identify a few species such as Stachybotrys and Chaetomium if they see the actual mold growth in the house.
As to whether the mold is bad, I would say all moulds are potentially a health hazard and should not be allowed to grow in homes or any environment where human beings spend a significant a mount of time. That does not mean people should panic whenever they see mould in their homes or offices. Most indoor molds will not infect humans or animals and therefore can only affect us through inhalation of airborne spores or if we ingest toxins produced by some molds during growth. Also, whether an individual is to be affected by mold or not will depend on other factors such as the amount of mold, the type of mold, duration of exposure and the individual’s immune system. Scientists estimate that only about 20% of the human population is susceptible to developing allergies, and is easily sensitized by normal spore concentrations (up to 106 spores/m3).
Growth of most indoor moulds is restricted to the surface of the materials they are growing on. It’s very likely that the mold growing in your basement is just on the outside. With damp conditions in the basement, mold will continue growing. You could try to use a dehumidifier to see if this could help to keep the basement relatively dry.