Carpets are an important part of any home, they offer comfort and bring warmth and character to living rooms, bedrooms, and stairways.
So what if you suspect you may have mold growing either on or under your carpet? Why has it happened in the first place? Is it dangerous? Can you remove it yourself and can the carpet be saved at all?
In this article, we will be answering all these questions and more, so for all you need to know about mold on carpets, keep reading.
What causes mold on carpets?
Mold grows on carpets for exactly the same reason it grows on any other surface, all its needs were met. It only needs a few things in order to not only live, but thrive on a surface, and they are:
A source of moisture
A source of nutrients
An ambient temperature between 60-80 degrees Fahrenheit
A lack of direct sunlight
Moisture can occur within a carpet for a number of reasons, spilled liquids, improper drying after cleaning, and the most common reason, water damage from flooding or leaks.
The level of moisture required for mold to grow is surprisingly low for some strains, as they only require a humidity level greater than 55%. In some states of the US, the humidity meets and exceeds this level on a regular basis, so even without liquids making direct contact with the carpet, the ambient humidity can be great enough to support mold growth.
Thicker carpets are more susceptible to mold growth, as the thick fibers lock in moisture and retain it for much longer, giving mold more opportunity to develop.
A source of nutrients
You may be wondering what mold could possibly use as a source of nutrients within a carpet, and the answer may be a little uncomfortable to hear.
There are of course simple ways that nutrients could find their way onto a carpet, such as dropped crumbs of food or other organic materials, but the most likely source of nutrients is actually from dead skin cells in the form of dust.
Dust made from our shed skin cells contains proteins, minerals, and oils that can all be used by mold as a source of nutrition. So if a carpet is not cleaned often enough, dust layers can build up and become a banquet for mold.
An ambient temperature
An ambient temperature between 60-80 degrees Fahrenheit is not necessary for mold survival, as many molds can live and breed either above or below this range, however, it is the most common temperature range that molds grow at their most rapid rate.
Unfortunately, it is also the most common temperature range US households set their thermostats to, providing the perfect environment for rapid mold growth through many months of the year.
In warmer states, the temperature stays within (and exceeds) this range for large portions of the year, giving mold plenty of opportunity to grow. Combine this with the higher humidity levels of these states (such as Florida), and you have the perfect storm for mold growth.
Lack of natural sunlight
The UV rays (specifically UV-C rays), will kill the vast majority of mold strains, this is why you find mold growing more often in darker areas of a property (although some strains are hardy enough to endure UV rays).
Areas of your home that receive the least amount of natural sunlight are more likely to be affected by mold growth if there is sufficient moisture in that area also.
As we will investigate later on, mold can grow under a carpet more easily, as it is a fungus and does not require natural sunlight to grow, cannot be harmed by UV rays, and usually has plenty of moisture.
What does mold look like on a carpet?
In the very first stages of mold growth, you may struggle to see any obvious signs of mold growing in a carpet. Once you can visibly notice mold growing on the surface of a carpet, it means that mold is well established underneath, and has been for some time.
Once the mold has become established, you may notice on (lighter colored carpets) small patches of green, black, or brown spots. On darker-colored carpets, you may see small patches of white-colored spots on the surface.
A more efficient way of detecting mold growth in or under a carpet in the early stages is to use your sense of smell. Once mold begins to grow, you will notice a distinctive musty odor that may remind you of an old basement or attic.
If you begin to notice a musty odor coming from your carpet, you must act immediately, as it could be possible to save the carpet before too much damage is done.
What types of mold grow on carpets?
Whilst there are thousands of strains of mold that could potentially have decided to make your carpet their home, there are three particular strains that you are far more likely to be dealing with.
The strains you are most likely to find growing on carpets are:
Cladosporium strains usually present with a dark brown to black coloration, and a velvet-like texture, and often grow in small, circular clusters that can group together if well established.
Penicillium strains typically are green, blue-green, yellow, or pink in color, with a velvety or powdery texture, and grow in circular clusters, often clumping together.
Alternaria mold often presents in dark grey to green coloration, with a downy texture, and grows in small circular patterns which can cluster together over time.
Is carpet mold toxic?
All three of the listed molds have the ability to produce mycotoxins as a defense mechanism. These mycotoxins can be toxic to both humans and animals and can cause a number of health complaints.
Individuals with allergies and those with suppressed immune systems are more likely to suffer from the more serious side effects of mold exposure, but even in healthy individuals, long-term exposure to mold and its spores can cause numerous health complaints such as:
For those with asthma, attacks can be brought on by exposure to mold spores, and continued exposure has been reportedly linked to some cancers. It is for these reasons that any suspicion of mold growth should be investigated and dealt with asap.
What kills mold on carpet?
There are plenty of products that have been specifically created to kill mold on carpets, and we will get onto some of these a little later.
First, I’d like to go through some of the natural options, as these can often be cheaper, more environmentally friendly, and just as effective.
Baking soda and white vinegar
Baking soda and white vinegar are excellent ways of both killing mold and removing the resulting stains. The vinegar is acidic enough to kill mold and its spores, and the oxidization of the baking soda helps to kill mold whilst getting underneath and lifting stubborn stains.
Steam cleaners use high-temperature water that is brought past boiling point and forced through a small nozzle to create a high-pressure jet.
The heat of the steam will kill mold and bacteria on contact, whilst the high-pressure jet will allow the steam to get underneath the mold and kill and remove it at its root.
Applying lemon juice is another proven way to kill mold. The high acidity level is sufficient enough to kill mold and the pleasant smell helps to tackle the unpleasant musty smell of mold.
Can moldy carpets be saved?
The good news is that in some cases, as long as the mold is caught early enough and treated effectively, a moldy carpet can be saved.
The problem is that it is very hard to detect mold in a carpet before the problem becomes severe, as by the time you notice anything growing on the surface, mold will be very well established underneath and within the carpet, and so the damage may already be done.
As stated, smelling an unusual, musty smell in one particular area of the carpet is likely mold growth and should be investigated quickly. If caught in time, you may be able to prevent any further spread and damage being caused.
How to remove mold from carpets
Removing mold on a carpet can be tricky due to accessibility issues, however, there are measures you can take to successfully kill and remove mold from carpets once it’s spotted.
Before we begin explaining the options available to you, there are a few safety precautions you need to be aware of.
Mold can be toxic, and when attempting to remove it yourself, you will be coming into close or even direct contact with it.
To prevent illness, it is advised that you wear the following protective equipment before you begin handling any carpet with mold.
A breathing mask
Eye protection (goggles)
With the safety talk dealt with, here is how to remove mold from a carpet.
Depending on the area affected, there could be a vast number of spores that once disturbed could float all over your property, leaving you with more mold issues to come in the future.
To prevent this, block off the affected room by placing towels under doors and covering gaps in door frames if possible (make sure this is safe to do so first).
Open all windows in the room you are treating to allow any mold spores to float outside, and if possible, place fans in the room you are working to ventilate the area and force as many spores out the window as possible.
Once ventilated, use a HEPA-filtered vacuum cleaner over the entire carpet. This will help to remove as many of the mold spores as possible before you come into direct contact, making the process a little safer.
Make a solution of one tablespoon of baking soda to one cup of white distilled vinegar and one cup of water. Depending on the area you are treating, you may need to increase or decrease the measurements but keep to the same ratio.
If you are dealing with mold under a carpet, lift the carpet to the point where no signs of developing mold can be seen on either the carpet or padding (underlay).
Liberally spray the affected area of the carpet or underlay with the baking soda/vinegar solution. Leave the solution to sit and work for at least 30 minutes. The acidity of the vinegar will kill the mold whilst the baking soda will oxidize and help to lift stains.
Once 30 minutes have passed, you can stub the area with a brush using a solution of warm water and detergent. This will remove any mold residue as well as help to reduce some of the odor from the vinegar.
Once the area has been thoroughly cleaned, it is vital that you dry the carpet as quickly as possible. Leaving the carpet damp would only cause the problem to return.
If working on a rug or small piece of carpeting, take it outside to allow it to air dry, preferably in the sun. If the carpet is much larger, a hairdryer can be used to quickly remove any remaining moisture.
After the area is cleaned and dried, it can be vacuumed once again to remove any missed remnants.
Should you use bleach to kill mold on carpets?
If you are wondering if bleach has the ability to kill mold on a carpet, then the answer is yes, using bleach will almost certainly do the job. However, bleach is also likely to stain and damage many types of carpets unless it is colorfast, so it is generally best avoided for this use.
If you are still certain you would like to use bleach, it would be wise to carry out a patch test, by testing a very small amount of bleach on a part of the carpet where a stain would be less obvious should it occur.
Bear in mind that although bleach may be the first product that comes to mind, the combination of baking soda and vinegar is quite powerful and usually more than sufficient to get the job done without any cause for concern over potential staining.
What products can you use to kill mold on a carpet?
So far we have discussed bleach and using baking powder mixed with vinegar to clean mold from carpets, but there are also specific products made for this task that may be worth considering, especially if you have already tried the approaches in this article.
There are many anti-fungal sprays available to purchase from hardware stores or on the internet. Many of these are powerful cleaning agents, so always make sure you check the label on the product to make sure it is safe to use on fabrics before beginning treatment.
Carpet cleaning solutions
Specific carpet cleaning detergents and solutions will do a good job of removing most of the molds from a carpet, however, they may not be as effective as using the vinegar and baking soda combination suggested. Whilst the carpet may appear clean, any spores left within the carpet will be able to quickly reestablish a colony.
Hydrogen peroxide is a powerful bleaching agent, antiseptic, and oxidizer. Diluted with water, it can kill mold by rapidly releasing oxygen, which breaks down the protein and DNA of the mold in a similar fashion to how baking soda works.
It is important to only use hydrogen peroxide diluted with a 1:1 ratio of water. Anything stronger than this can cause damage to fabrics, including carpets.
How to prevent mold from growing on carpets
Cleaning mold from a carpet can be a tricky business, and as we have discussed, once you can visibly see it forming on the surface of your carpet, you may already be too late to fix the problem.
Preventing mold from growing in the first place is certainly preferable, to having to treat it once it arrives, so, if you are concerned about the potential for mold growth in your carpet, or have had to deal with it and don’t want to again, take the following precautions.
Keep it dry
Keeping the moisture levels as low as possible is one of the easiest ways that you can prevent mold and mildew from growing in carpets of all kinds.
Any spilled liquids should be cleaned up and leaks should be fixed in both cases the carpet should be dried as quickly as possible. Consider using not only hairdryers and heating to speed up the drying process, but dehumidifiers too, as they actively draw out moisture from the room.
If you live in a humid climate, moisture can be a real problem. If you have had to deal with moldy carpets on a frequent basis due to high humidity levels, then consider having a dehumidifier in the room for the higher humidity months of the year. This will help to decrease the overall moisture levels in the room. As long as you can keep the humidity below 55%, you can slow the progress of mold growth, or even halt it entirely.
Keep it clean
Mold needs food, and without it, it cannot grow and spread. So, by vacuuming the carpet (preferably once per week), you ensure that any dust, dropped food or organic matter that has been walked into the home will be removed, taking the molds food source with it.
If possible, use a vacuum cleaner with a HEPA filter attached. This is a special filter that is small enough to remove mold spores and other allergens. If any mold spores have found their way into your home and have settled ok the carpet, with a HEPA filters vacuum, you can remove them straight away before they have a chance to establish a colony.
Ventilate the area
Fresh airflow will not kill mold or remove it, but what it does do, is help to keep moisture in the air flowing through the property, rather than letting it settle and condense in one place. It also prevents mold spores from being able to settle in one location as easily.
Improving your property’s ventilation is not usually a complex process. You may need to add vents to allow fresh air to enter the room from the exterior, but sometimes simply leaving doors and windows open for a period to allow a fresh circulation of air is all that’s needed once in a while (as long as it is safe to do so of course).
When to call a professional
There are points where cleaning the mold out of your own carpet will not be possible. This is usually when the extent of the mold growth is too vast to be treated by one person, and when staining has occurred that cannot be removed with either natural or store-bought products.
If you have attempted to remove mold from your carpet yourself and have not been successful, you have two options. You can either throw the carpet away, purchase a new one and use the preventative measures to stop this from happening again in the future or, you can hire a professional to try and save the carpet.
Professionals have specific tools and chemicals that may be able to remove the mold and the stains caused by it but bear in mind that in many cases, the damage done to the carpet may be irreversible, and even professional assistance may not be able to save it.
Can mold on a carpet spread?
Mold under a carpet can spread very rapidly if left untreated. If the conditions are correct, mold can begin to grow and spread within 24-48 hours. Carpets in high-humidity areas such as bathrooms and near kitchens should be inspected every few months to check for any signs of mold growth.
How common is mold in carpets?
Mold growth in carpets is very common due to the thickness of the carpet fibers trapping moisture and dust particles. It can sometimes be difficult to spot in its early stages, as it tends to grow underneath the carpet first, only showing on the surface once it is firmly established.
What kills mold instantly on a carpet?
To kill mold instantly on carpets, use undiluted distilled white vinegar. The acidity of the vinegar is powerful enough to kill mold, but will not damage the fibers of the carpet. Vinegar sprayed directly onto the affected area of the carpet will take no longer than one hour to kill the mold.
Does moldy carpet need to be replaced?
In many cases, a moldy carpet can be saved if it is treated quickly. However, once you visibly notice mold growing in a carpet, it may already be too late, as the mold will already be well established underneath. Once you smell mold, treat the carpet immediately in order to save having to throw it away.
Treating mold in or under a carpet can be a challenging task due to it being difficult to detect until it is already well established. Using vinegar can be an effective way to treat mold that is detected early enough, however in many cases, either a professional may need to be called in order to save the carpet, or you may need to throw it away.