Mold is everywhere. It is known as nature’s recycler. Mold’s purpose is to break down dead organic matter, toppled trees, dead animals, fallen leaves, grass, plants and the like, into soil. Without mold these materials would take much longer to decay and become soil.
There are about one thousand species of mold in the United States. The most press has been given to “Black Mold”, officially known as Stachybotrys chartarum. Stachybotrys receives so much attention because it is one of the many mycotoxin producing molds. Mycotoxin’s are what physicians believe cause the negative health consequences to humans. Mold is not very problematic to our health as long as it is kept out of doors. Health concerns proliferate once mold enters a structure.
The way mold reproduces is through mold spores, which are basically mold seeds. A mold spore is much like a dandelion plant in which the dandelion seeds blow away in the wind. The difference is that a mold spore is much smaller; allowing the air to carry it anywhere there is air and air movement. A spore is not visible to the human eye but can be seen under a microscope. Mold Spores measure between 2 and 20 microns in diameter. Just to give you a reference point a human hair is about 75 microns in diameter.
Due to the size of mold spores they travel wherever air currents flow. Even very healthy homes with no history of water incursions have some mold spores inside of them. Homes with mold actually growing have a much higher number of mold spores in them. This “mold spore loading”, in homes with mold constantly replicating, is the reason people have failed attempts at remediating mold themselves. They remove all visible molds: some wipe off walls with bleach, vinegar, or peroxide and they think the problem is gone. However a few days later the mold is back. This too is the reason mold remediation is so expensive. In order for it to be successful, re-mediators are charged with removing all mold spores from the area.
Mold requires moisture in order to grow. If any organic material in your home (wood furniture, wood framing, the paper on gypsum wall board or on insulation) should become wet the material could grow mold. In light of this the easiest way to avoid mold in your home is to keep everything dry. Water leaks and flooding are out of our control, however there are ways houses get wet enough to grow mold which are in our control.
Every winter we receive requests to check homes that have mold on exterior walls. When we check the homes we find that the exterior walls are very cold and condensation has collected on the wall. Just like a glass of ice cold water will collect condensation on it in the summer so will a cold wall in the winter. The result of the moisture, given time to replicate, is mold growing on the wall. To avoid this scenario keep the temperature in your home at least 67 degrees in the winter and check your exterior walls to see if they are cold. If they are cold turn the heat up or increase air flow on the walls. Warmer room temperatures help to keep the walls drier by not allowing moisture in the room to condense on the wall. Additional air flow from a ceiling fan or turning your furnace fan on will help to warm and dry the walls. Another problem is placing furniture directly against exterior walls. Leaving a few inches between the furniture and the wall will encourage air flow, assisting to keep the wall warm and dry.
Homes are also built with greater air tightness now than they were 40 years ago. As a result excess moisture needs to be removed from homes. Bathroom fans were not so important 40 years ago because houses leaked enough air that that they dried out. In newer homes moisture will stay there unless it is exhausted outdoors. Every bathroom should have an exhaust fan wired directly to the light switch so that the excess humidity from showering can be removed from the home. Importantly, if you have an exhaust fan already installed make sure that it exhausts outside, not in the attic. By blowing moisture into your attic you are simply moving your problem to a different location.
Another source of excess moisture in homes is from laundry dryers venting inside the home. They make lint capture devices so people can have their dryer vent inside the home and some people like this idea because the dryer vents moist warm air. These vents are responsible for large amounts of moisture staying inside the home and most often are used in the winter when this excess moisture can condensate on the exterior walls of the home. Make sure your dryer vents outside.
The final source of excess moisture is in crawl spaces. Crawl spaces are difficult to manage humidity in and the result is mold on the sub floor and floor joists. If you have a crawl space on your home the easiest way to manage humidity is to place a vapor barrier over all earth in the space. Earth gives up moisture at an incredible rate allowing humidity in crawl spaces to get above the mold threshold of 60 percent relative humidity. Often even if there is a vapor barrier in the space it has holes and tears in it. Old vapor barriers in bad shape are only minimally better than no vapor barrier.
In summary, mold is much easier to keep out of your home than it is to remove once you have it. If you have any question about areas of your home being prone to mold we provide free guidance and moisture checks to help prevent the occurrence of mold.
By Tim Evens