Mold In Your Cellar?

water-damaged-basement-wallThere are wet clothes on the line downstairs. Last night’s rain storm left a few puddles on the floor near the cellar windows. It feels a few degrees warmer in the cellar than in the kitchen because it’s more humid. Situations like this create a breeding ground for mold, one of the fungus kingdom. Molds are everywhere, and are a common component of dust. Large quantities of mold can become a health hazard, causing allergic reactions and respiratory problems. Those few that produce mycotoxins can pose a serious risk to human health, and are the “toxic molds” of conversation. One of the most infamous is called Stachybotrys chartarum, more commonly found outside than in, but an occasional resident of flooded buildings. Molds can live on plants, foods, dry leaves, and other organic matter, but can also grow on hard surfaces.

Molds are produced by spores, which can be carried by air currents because they are tiny and lightweight. Fungi in general are necessary to the food chain as decomposers. But as molds inside your house they can cause a myriad of problems. For significant mold growth to happen there needs to be a source of dampness, a source of food, and a substrate capable of sustaining growth. Building supplies, including carpets, plywood, sheetrock, and other porous materials, are ideal places for molds to live and grow. Cellulose is one of their favorites. A single incident of water damage can encourage mold to live inside a wall, later to be resurrected from near dormancy by high humidity. Identifying the source of humidity is an important step in resolution. Even the steam from a stovetop or the shower, the watering of houseplants or the use of a central humidifier can exacerbate—or even initiate—a mold problem.

The health effects of mold exposure include allergic reactions, eye and respiratory irritation, infection, and toxicity. About five percent of individuals are predicted to have some airway symptom from molds over their lifetimes. Wherever and whenever mold infestation is identified it needs to be remediated.

If the cellar is where the kids play when the outdoors is uninviting, paying attention to the presence of mold is important. If enough is there, you’ll be able to smell it, even if you can’t see it. If the mold is growing in black streaks and looks slimy, it could be Stachybotrys chartarum, and is usually indicative of poor indoor air quality. If the texture is fuzzy or matte, it’s likely another strain, such as Aspergillus or Fusarium. Regardless of what it is, it is advisable not to touch it or to inhale deeply when you examine it.

Sometimes you’ll see condensation on your (cellar) windows or walls. This might mean there’s a combustion problem with an appliance. Is the dryer properly vented?  How about the furnace and water heater?  Too little air to the furnace can cause back drafting, which is also a carbon monoxide threat. Using a de-humidifier in the cellar, especially if it’s unheated, is sound practice. If your dryer is vented into a bucket of water to trap lint because outdoor venting is difficult or impossible, and if the cellar lacks heat, the damp air from the dryer can condense once it contacts the cold walls. Hence the rationale for a dehumidifier. A fan can desiccate the air enough to deny mold a happy home.

The dryness of indoor wintertime air can cause static electricity, shrinking and warping of furniture, skin irritation, and even bloody noses. At 40% humidity, most of us are reasonably comfortable. Increasing indoor humidity to prevent problems is O.K. as long as there is no condensation inside the living room windows. Cold air cannot hold much moisture, and a heater dries it out even more. Being overzealous with humidification can create conditions favorable to mold, which prefers temperatures between 77° F. and 85° F, but can survive anywhere between 32° and 95°.   Unless there are symptoms of mold sensitivity, testing is unnecessary. If it is done, it should be performed by a trained professional. In a baseline home, mold spore counts may range from 300 to 1200 spores per cubic meter. Counts above 1000 suggest a mold problem. (Rockwell, 2005)  On the other hand, there are no regulations that outline acceptable mold counts

Simple steps to remedy a small occurrence start with sunshine, improved ventilation, additional insulation in the walls, and dehumidification. But these do not get rid of what’s already present; they only make it non-viable. Simply killing mold is not enough. It has to be removed because the chemicals and proteins that evoke a reaction are still present in dead mold. Using bleach will only make it lighter in color and fail to kill the roots. Why?  Because bleach is mostly water, and water is what mold needs to thrive.  The active ingredient in bleach, often sodium hypochlorite, is weakened. A stronger product than what we get from a store is dangerous. Not only that, bleach will only work on non-porous surfaces, like tubs and tiles. It does not penetrate porous materials, even concrete, so it can’t get to the roots, and the mold will return. It does, however, change the color. Some people think that if they can’t see any mold, all is well.

Borax and straight white vinegar can kill mold, but you have to be patient. Borax has to be mixed with water, but is strong enough and safe enough to do the job. Neither product needs to be rinsed. If you don’t care about spending money, tea tree oil is a great antifungal, using a teaspoon per cup of water in a spray bottle. It’s safe to humans and animals, and is one of the best mold slayers. People use it on cuts and scrapes because it’s also antibacterial. Any residue will prevent recurrence of mold. A novel product in the fight against mold is grapefruit seed extract, used to fight bacterial, yeast and viral infections. The citric acid seems to be the active component. Ten drops of this go into a cup of water in a spray bottle. It’ll kill the mold down to its roots. If a mold problem is severe, get a professional to do the job, but make sure he’s qualified.


Hardin BD, Kelman BJ, Saxon A.
Adverse human health effects associated with molds in the indoor environment.
J Occup Environ Med. 2003 May;45(5):470-8.

Koburger T, Below H, Dornquast T, Kramer A.
Decontamination of room air and adjoining wall surfaces by nebulizing hydrogen peroxide.
GMS Krankenhhyg Interdiszip. 2011;6(1):Doc09.

Kuhn DM, Ghannoum MA.
Indoor mold, toxigenic fungi, and Stachybotrys chartarum: infectious disease perspective.
Clin Microbiol Rev. 2003 Jan;16(1):144-72.

Mudarri D, Fisk WJ.
Public health and economic impact of dampness and mold.
Indoor Air. 2007 Jun;17(3):226-35.

Robbins CA, Swenson LJ, Nealley ML, Gots RE, Kelman BJ
Health effects of mycotoxins in indoor air: a critical review.
Appl Occup Environ Hyg. 2000 Oct;15(10):773-84.

Rockwell W.
Prompt remediation of water intrusion corrects the resultant mold contamination in a home.
Allergy Asthma Proc. 2005 Jul-Aug;26(4):316-8.

Terr AI.
Are indoor molds causing a new disease?
J Allergy Clin Immunol. 2004 Feb;113(2):221-6.

U.S. Environmental Protection Agency
“A Brief Guide to Mold. Moisture, and Your Home”

*These statements have not been evaluated by the FDA.
These products are not intended to treat, diagnose, cure, or prevent any disease.

Print Friendly, PDF & Email