The Five Top Myths About Mold

As a home inspector, I get questions all the time about mold. They range from “How do I get mold off the shower door?” to “Is that dark stuff in the basement Black Mold?” Home inspection experience plus a little science study reveals some surprising answers.

Here are the top five questions, and my answers.

  1. Mold always smells bad. True or False?

False. It takes a while for mold to invade enough material to smell. It’s not the mold that smells, by the way, but the material that it spreads to that smells. Who of us has not pulled back a carpet only to find crusty mold and “that smell” underneath? It is the moisture that drives the mold growth, and the moisture then drives the rotting of materials such as carpet, wood, and drywall.

  1. I can prevent mold from growing by keeping a disinfectant on surfaces. True or False?

False. Mold growth is driven by humidity. Water molecules in the materials (walls, carpet, baseboard) feed strains of fungi that thrive in low light, high humidity environments. Using disinfectant only delays surface growth, while more growth is taking place inside the materials themselves.

  1. All mold is dangerous. True or False?

False. Our lives are full of mold spores floating around in the air both inside and outside. Mushrooms are fungi, and I bet you’ve had some on your salad. The key is balance. If mold spores are allowed to “take over” in an environment that feeds them, then an enormous number of spores are produced. Breathing an overabundance of fungi spores can cause a variety of health problems.

  1. Black mold is the most dangerous mold. True or False?

False. Fungi color has nothing to do with it’s toxic properties. Rather, it is the extent and variety of the mold that creates problems for humans. For example, a green mold growing in your shower is unlikely to cause a problem but looks bad. But if your basement has a water leak in the wall and over time mold has taken over the insulation area, then the mold could be producing enough mycotoxins to be a health hazard, no matter what the color is.

  1. Air filters can help stop the spread of mold in your home. True or False?

False. If you have a mold problem in your home, it means that moisture is driving mold growth. The only way to stop mold growth is to take away the moisture.

What to do about mold?

  • Measure the humidity in the areas where you have mold, or suspect mold. If the humidity is more than 60%, you are providing a ripe environment for mold growth. Consider installing a dehumidifier to bring the level down to 45-55%.
  • If you already have a serious problem with mold growth, call a professional to clean and remediate it. This is not a job you want to try yourself.
  • While bleach products do work well on mold, it’s a strong chemical that you should not be breathing. Regular soap and water will work. If you have carpet that is moldy, it should be pulled up, the area cleaned, and new carpet or another type of flooring put down.

The key to keeping mold at bay is moisture control. Run the air conditioning, run a dehumidifier, and run the vent fan in bathrooms during use.