toxic mold on house walls

Mold in Your Basement or Crawlspace: What is It and What You Should Do About It?

It began as a small black dot in one of your crawl space floor joists. You shrug it off, thinking that it was just a smidge of dirt that will go away on its own. Now this monster has grown, and the entire flooring is covered with gray patches. A musty smell emanates from your crawl space, a smell that never goes away no matter how much air freshener you use. You and your family members developed allergies too. If this situation seems familiar, it’s time to check your crawl space for toxic mold and address the situation.


The organism that we now refer to as mold is a type of fungi which grows to a long and branching structure called hyphae. Molds are everywhere—in your kitchen, bathroom, pantry, office, supermarket, and more. These organisms are essential as they secrete digestive enzymes to break down organic matter. Think of them as Mother Nature’s natural recycling systems, breaking down dead matter to make room for new ones. They thrive in moisture-rich and poorly ventilated places in your home, such as the kitchen, the attic, the basement, the bathroom, and the crawl space. But how do these organisms spread and multiply, and when do they become toxic?

Just like other fungi, mold release spores to reproduce. Once spores are released, they only have to find a dark and moist environment to survive. Wood, dust, wallpaper, leather, and other organic matter can serve as their food. They just need a little oxygen and a lot of humidity to thrive. With the right conditions and temperature and an abundance of food, your house could become a host to a mold colony within a couple of days.

There are non-toxic types of mold, but there are some that could harm your health. Some of the relatively benign types are those that cause allergies. Mold spores and hyphae (the thread-like growth) contain protein allergens. These allergens are also released into the environment as the colony grows. People suffering from asthma and allergic rhinitis or hay fever find that the presence of mold exacerbates their condition. Some types of molds can cause allergic reactions, respiratory infections, headaches, low-grade fever, or general malaise. “Toxic” molds or molds with that release high concentrations of mycotoxins are particularly dangerous for the health. Some fungi release a chemical called trichothecenes which can cause throat irritation, chest pains, dermatitis, and asthma-like symptoms.


A mold colony does not appear overnight. It usually starts out as a small dot that homeowners mistake as dirt. As the days pass, they slowly—yet under the right conditions—form a colony. Before you know it, there’s an ugly gray or white growth on the wall, the ceiling, or in the flooring (in the case of basements and crawl spaces). Detecting mold growth is especially hard when it grows in an enclosed area of the house such as the crawlspace. Apart from an unsightly mold colony, some of the tell-tale signs of mold growth include:

Moldy or musty odors. The chemical is this particular odor is called microbial volatile organic compounds or MVOCs. While the smell doesn’t cause respiratory disorders, it can cause headaches. If a mold colony has grown in a crawl space, the smell can also be embarrassing to homeowners as they cannot pinpoint and get rid of it easily.

Another sign of mold growth in your house is the presence of condensation. Excessive moisture which had escaped from pipes and windows can contribute to the growth of the fungi in your home.

If your utility bills had recently spiked, there might be a water leak somewhere in your house. One of the first places to check is the basement or the crawlspace. If neglected, your basement or the crawlspace can become the perfect place for a mold colony to flourish. Moreover, the presence of mice, roaches, and other pests can be a red flag that your crawlspace or basement is not in good shape and you need to do something about it immediately.

How to Prevent Mold Growth and What Should You Do About it if Your Crawl Space/Basement is Already Full of Mold

To prevent mold growth from turning your house into an unlivable mess, consider the following:

  • Install adequate lighting in your basement or crawlspace so you can check it every now and then.
  • Install a humidity sensor to maintain proper humidity levels.
  • If your crawl space has a dirt floor, ensure that it is covered by pouring concrete on it or installing a vapor barrier.
  • Keep in mind that your crawlspace or basement is a part of your house. Keep it meticulously clean just like other parts of your home.
  • Clean up and dehumidify the crawlspace immediately after a flood or in case of sewer backup. This can be done by professional cleaning service providers in your area.

crawl space vapor barrier

If your crawl space, basement, or any part of your house has become a host for a mold colony, book an appointment with your professional cleaning service provider immediately. Your regular domestic cleaning provider may not be of much help in getting rid of mold as this is beyond their domain. Professional basement and crawlspace cleaners go beyond simple cleaning to provide proper waste disposal, removal of mold-infested parts of your basement or attic, and proper insulation. Contact your cleaning provider today to get rid of mold in your basement, crawlspace, or any other parts of your house.