Is this Mold or Mildew

“That’s not mold, that’s just mildew!” – this is a phrase I hear every day on the job. There is a huge difference between these two fungi, but at some point throughout history the terms ‘mold’ and ‘mildew’ began to be used interchangeably. It’s important for you to know the difference between the two and why you don’t want either growing in your home. Luckily, Mold Medics is your first stop to finding the best practices on how to avoid mold and mildew.

What differentiates mold from mildew?

Mold Growth on Drywall above Window

Mold and mildew are everywhere in our environment but what they feed on differentiates the two fungi. It is estimated that there are over 100,000 different types of mold found around the world and new species are discovered regularly. I like to call mold the ‘OG’ when it comes to recycling. Without mold we would have miles upon miles of organic material piled up on the earth’s surface. Mold and mildew have a necessary place in this world, inside our homes is not one of them. One of the problems with mold is that it shows no bias. Mold doesn’t recognize that your leather shoe is different from a dead carcass on the highway or a fallen tree from your bathroom vanity. Mold feeds on non-living organic materials. This ‘non-living’ food source is how we determine the fungus is mold instead of mildew.

Powdery Mildew on Leaf

On the other hand, mildew is a type of fungus that only grows on living plants and is considered a parasite because it feeds on a living organism. Unless you have an abundance of house plants, or you live in a greenhouse, you most likely don’t have a mildew issue since mildew needs a living host to feed off of. So that substance on the caulking in your bathroom, the growth on the sheathing in your attic, or the stain in the corner of your basement is not mildew, it’s mold.

Why you don’t want mold or mildew in your home.

Whether you have a mold or mildew issue in your home neither is good for you home or your indoor environmental quality. Both should be eradicated.  Having different types of fungus growing on building materials, personal contents or house plants should be a concern to any building occupant. According to the EPA the average American spends approximately 90% of their lives indoors. To make matters worse, indoor air quality can be 2 to 5 times worse than outside air!

In regards to mold or mildew, there are three different routes of exposure. Inhalation (by breathing), Ingestion (by swallowing) and absorption (through the eyes or skin) are the three ways these fungi can enter your body. Inhalation is the most frequent rout of exposure and we need to breathe air at all times. Mold does not affect everyone the same and there are ongoing studies on the exact health effects of exposure. While everyone should avoid exposure to high levels of indoor mold people at the highest risk are young children, pregnant mothers, elderly and immunocompromised individuals. In later articles we will discuss the different allergenic, toxigenic and infectious potentials of mold exposure.

At this point, let’s agree that having a fungus growing in your home, and exposing yourself and family to the byproducts, cannot be good for your general health. Aside from the obvious solution of remediation, there are some things that you can do to prevent both mold and mildew.

Best Practices to avoid mold growth

In the United States, we have thousands of different types of homes and buildings. We have borrowed styles from around the world and create our own as well. Each type of building has its own set of challenges in regards to mold. In later articles, we will discuss specific ways to avoid mold in attics, basements, crawlspaces, bathrooms, and living spaces. In this article, we will discuss some basics about what is needed for growth and best practices to create an environment that is non-conducive to mold growth. For mold and mildew growth you need three ingredients (moisture, a food source and air). To keep things simple, let’s concentrate on moisture since it is the most important ingredient to control in regards to mold and mildew. For mold prevention, we want to make sure no liquid water in entering the home. Ways we can control water from entering the home is by ensuring there are no roof leaks, gutters and downspouts are functioning properly and grading around your home is sufficient.

Next, let’s move into the home and make sure there are not active leaks. Check plumbing and appliances. Check to see if the foundation of the home is compromised in any way. Beyond liquid water we also need to pay attention to water vapor. High humidity in a building can cause widespread issues. The EPA’s ideal range of relative humidity in a building is between 30%-50%. You should not have the relative humidity above 60% for prolonged periods of time. There are other considerations to indoor humidity and why you would not want humidity below 30%.  A sufficient sized dehumidifier for the structure is a great way to keep relative humidity maintained at proper levels. Also, all spaces within the structure need to be properly conditioned to avoid dew point being met.

Preventing Mildew

Preventing mildew on the other hand, is much more simple. For avoidance of mildew, limit the number of plants you keep indoors. Pay attention to indoor conditions and monitor the plants to ensure a white powdery substance doesn’t start to form on the plants. Make sure that any houseplants are kept healthy and in good condition. Check this out for more information on treating mildew. As always, if you have any questions or concerns don’t hesitate to reach out to a professional for help.