While mold on hard surfaces like metal or tile is usually easy to remove, getting rid of mold from carpet fibers can be tricky. Not to mention, mold often starts growing on the carpet backing, where it can go undetected for days or even weeks until the infestation is widespread. Conventional wisdom often attributes carpet mold to water damage or high levels of humidity – and suggests that ridding the mold of the excess moisture will take care of the mold problem. However, moisture is only half of the moldy carpet equation. With the right tools and methods, carpet mold can be surprisingly easy to keep under control. 

Moisture + Dirt = Mold 

A recent scientific study sponsored by the Carpet and Rug Institute (CRI) offers valuable insight into how mold grows in carpeting – and how best to avoid it. During the study, entitled “Carpet, Moisture, and Mold,” tests were conducted to determine whether high humidity (like you might find in an unfinished basement) caused mold growth on carpeting. Researchers subjected carpet in various conditions – new, old, soiled, and clean – to various levels of humidity. In particular, the researchers wanted to see if high levels of humidity (defined as 80% or higher) provided mold and mildew with an incubator in carpeting. 

Astonishingly, what they found was that dirt, more than humidity, contributed to mold growth. Carpets that were dirty (even lightly soiled) bred much more mold than clean carpet when exposed to the same levels of moisture. In short, high humidity plus dirt equals mold. It’s important to note that if a carpet is clean enough, it can be highly resistant to mold growth, despite humid conditions. In the CRI study, clean nylon carpet was subjected to high temperatures and levels of humidity (80 degrees Fahrenheit; 80% humidity), and no mold growth occurred. Even clean carpeting that was known to have active mold spores did not support additional mold growth in the course of the CRI study. Why is this? Well, dirt on carpeting grows mold for a couple of reasons. First, dirt is loaded with mold spores. Second, dirt is a hygroscopic material, meaning that it readily attracts any available water from its surroundings. In other words, dirt is an absolute moisture magnet. And when the moisture in the dirt found in carpet is combined with the room’s ambient humidity, or with excess moisture from a leak or flood – mold has the right conditions to thrive. 

Health Impacts of Moldy Carpet 

If left untreated, exposure to mold can impact your health in several ways. Mold releases allergens and can even emit toxic substances called mycotoxins. If touched or inhaled, mold can result in throat, skin, and eye irritation, as well as coughing, wheezing, and nasal stuffiness. In more severe cases, when coupled with a weakened immune system, mold inhalation can even cause respiratory infections or bronchitis, and exacerbate symptoms in asthmatics. 

Related: What Are Mycotoxins? 

How To Prevent Carpet Mold 

Vital Oxide is your secret weapon against carpet mold – and every other mold for that matter! Vital Oxide has the The Carpet and Rug Institute (CRI) Seal of Approval, is safe for stain-protected carpet and fabric finishes, and can be used as a carpet pre-spray, or in a tank with hot water vacuum extraction units. Vital Oxide works by means of oxidation; its non-ionic formula will not break down acid dye blockers in carpet fiber, which helps preserve your carpet’s color. It’s highly effective against mold, as well as urine stains and odors, smoke odors, pet dander, and dust mite allergens. Vital Oxide is carpet mill tested and approved and leaves carpets smelling fresh. 

Carpet mold can be nasty stuff. Thankfully, there are a few simple steps you can take to help prevent it from happening in the first place: 

• Before installing carpet in your home, do your homework. Be sure to choose moisture-resistant padding and ensure that it’s installed correctly.
• Consider installing synthetic carpet. Organic carpet materials (like wool) are more prone to mold growth than synthetic carpeting such as nylon, polyester, or polypropylene (sometimes called olefin). 
• Avoid installing wall-to-wall carpeting in areas where moisture is often present, like an unfinished basement or a poorly ventilated bathroom. Instead, use washable throw rugs in damp rooms and launder them once a week with an Anti-Allergen Laundry Detergent. 
• Help keep dirt out of your carpet by making your home a “no-shoe zone” – try to get in the habit of always removing your shoes at the door. 
• Keep the temperature in your home below 80 degrees Fahrenheit. Temperatures above 80 degrees Fahrenheit can contribute to mold growth in carpeting. Plus, air conditioning can help with both temperature and moisture because it lowers humidity as it cools the air.
• Keep your home well-ventilated by opening your windows for at least a few minutes each day. This is an easy way to reduce moisture in your home – unless you live in a humid climate, that is! 
• Regularly replace your home air filters. HEPA air filters can remove allergens such as dust and mold. 
• Vacuum floors at least once weekly with a HEPA vacuum to capture dirt, dust, and allergens. 
• Deep clean carpets at least twice yearly – or as often as needed. Use a carpet cleaner or hot water extractor along with Vital Oxide to sanitize. Vital Oxide is safe for use on stain protected carpet and fabric finishes, and can be used as a carpet pre-spray, or in the tank of hot water extraction units to sanitize carpet. When using a carpet cleaner or hot water extractor, follow the manufacturer’s instructions on how to clean for best results. Vital Oxide can be added directly to the tank of the hot water extractor to sanitize, either full strength, or diluted 1 part Vital Oxide to 5 parts water. Allow to dwell for 10 minutes. Do not rinse, use an extraction wand and dry stroke carpet to remove excess moisture. Allow carpets to air dry for at least eight hours (ideally overnight), or use circulation fans to speed up the drying process. This is a very important step in the battle against carpet mold. Unless you actively work to dry a wet carpet using fans, a hot air drier or a dehumidifier, a wet carpet will stay wet. And it will not take long for a wet carpet to form mold.

NOTE: Before using any cleaning product on carpet, always test it on the fibers in an inconspicuous spot to make sure it does not cause discoloration. Spray the solution on the fibers. Let it sit for five minutes and then blot with a clean white cloth. If there is color transfer, do not use the product on your carpet.

Should You Hire a Professional to Treat Carpet Mold? 

For extensive mold problems, consider hiring a professional who is trained in mold cleanup. Some molds are highly toxic, and even less dangerous molds can cause problems for people with allergies or those with compromised immune systems or respiratory issues. Generally, the rule of thumb is to seek the help of a professional if the mold covers 10 or more square feet. Removing large mold colonies requires specialized equipment and tools. Local public health departments can offer advice on mold testing and refer you to an expert mold remover. Always err on the side of caution when it comes to major mold issues. 

How to Get Mold Out Of Your Carpet 

If you have a minor case of carpet mold, you’ll usually be able to tackle it yourself. It is essential to wear proper safety gear when removing mold. Gloves, safety goggles and a respirator mask are needed, because the process of cleaning up the mold will release a lot of mold spores into the air, and without proper protection, you could have a severe reaction to the mold spores.

If the mold is black and fuzzy, or if there is an intense musty smell, the infestation might be much more serious than a minor nuisance. First, the area should be opened to check for structural damage. Any building materials that need to be removed should be bagged in heavy-duty plastic bags and disposed of properly. Allow the area to dry out thoroughly and make any needed repairs. It’s also essential to ventilate and, if possible, to isolate the area properly. The goal is to prevent mold spores from spreading throughout other parts of the house, but still keep the area well-ventilated. Close doors or use plastic sheeting to block off some areas, and use fans to blow air out an open window or door that leads outside. 

To clean and remove mold from synthetic carpet such as nylon, olefin, or polypropylene (always seek professional help for wool carpets), first vacuum with a HEPA-type vacuum cleaner (a non-HEPA vacuum might not properly contain mold spores) and then use a steam cleaning machine or extractor machine to remove excess soil. Next, apply Vital Oxide to the carpet (first test for color fastness in an inconspicuous area) and allow it to dwell for 10 minutes. Do not rinse, instead use an extraction wand and dry stroke carpet to remove excess moisture. Allow the carpet to dry completely. 

Carpets with a severe mold infestation should be removed completely and properly disposed of. Use a wet/dry vacuum to thoroughly clean the underflooring and then spray with Vital Oxide and allow it to air dry for several days before replacing flooring.