Can Mold Grow Under Vinyl Plank Flooring?


One of the scariest words in a homeowner or a landlord’s dictionary is the word mold. Having mold in your home means that you are more than likely going to be spending thousands of dollars to make the problem go away. We can wish it out all we want, but unfortunately, we cannot put a band-aid on this problem, as it causes health issues within ourselves, like in the respiratory system or allergic reactions. Not to mention the smell is just awful!

So the question we will be going over today is, can mold grow under vinyl plank flooring? Although vinyl plank flooring is well-known to be waterproof, it does not mean that liquids can seep through the cracks, grooves, or edges and become trapped under the planks, allowing mold to grow underneath your floors. When mold forms, it is mostly due to being around the tub or toilet, which is the best mold environment. 

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Although this is a possibility, it does not mean that we cannot take the necessary precautions to ensure mold does not grow under our vinyl planks. What can we do to prevent and solve this issue, and is it dangerous when mold is formed underneath vinyl flooring? Continue to learn all there is to know on this subject.

How Can You Tell If You Have Mold Under Your Floor?

If you suspect there is mold growth under the floors, then the best thing to do is check it out in these few simple yet effective ways. Keep in mind that mold may not always be visible like we wish, but there are many ways you can tell if mildew is under your floors. The primary method is to be vigilant about where water will be the most, especially in more humid areas, such as the kitchen or bathroom areas.  

That said, here are some excellent ways to tell if mold is within your home:

  • Watch out for a musty smell: One of the most significant ways to see if there is mold is by your sense of smell. It will be very unpleasant and most likely resembles something similar to wet socks, meaty scent, rotten wood, or anything that seems to be earthy-like. It may not be intense at times but should be noticeable enough to tell. One way to do this is by going to sinks or toilets, kneeling, and giving a quick sniff. 
  • Keep an eye out for visible signs: Usually, this contains a dark spot in one specific area, stains on the grout of tile floors, velvet textures for wood surfaces, or distinctive coloring texture (dark green, black or brown, and sometimes yellow or orange.)
  • Test the affected area with bleach: A relatively quick way to test for mold is by swabbing the area with bleach and dab it on the wall (use 1 part bleach, 16 parts water.) If the spot lightens within a minute or two and keeps coming back after cleaning, then it is safe to say this is mold. If the area does not move, then it is more than likely dirt.
  • Alternatively, use a mold testing kit to detect a mold presence and type of mold within your home.
  • Watch out for any symptoms in your own body: Meaning that you may feel as if you have a sickness that won’t go away, your allergies are always acting out, any asthma you may have is getting worse, and there is no explanation, your body is itchy, or you may be constantly tired.
  • Check for any leaks in plumbing: Lastly, there may be a plumbing issue, and you may not know it. Watch the water bill to see if it mysteriously goes up and check every pipeline that might leak somewhere, as this source may be feeding the mold. 

Consider a Moisture Barrier

One of the main ways to prevent your vinyl plank flooring from growing any mold is by considering a moisture barrier. You can quickly get these at a fairly reasonable price, and some of the underlayment companies have warranties provided, so it would be more worthwhile investing in it to ensure better safety over your wood-looking floors.

There are many benefits as to why you should invest in one, which include:

  • Prevents mold and odor: The main reason we recommend and underlay is that it prevents mold and odor. It can cause a lot of damage, as mentioned previously. It can also better eliminate the smell in your home. 
  • Protects pipes: When moisture gets in contact with the lines stored in your crawlspace, it can damage the pipes, causing them to break or burst. As learned, mold can form because of this. Having a moisture barrier, for this reason, is explicitly keeping those pipes dry, which increases their lifespan and saves you money in the long run.
  • Pest control: If the floors are not sealed, it may cause unwanted rodents to enter your home, which in return, can be severe issues, such as chewing through the wires or health problems. Installing an underlayment closes off any crawl spaces, leading to better elimination of this issue. 
  • Provides better temperature control: Any moisture that gets into your home’s passageway can significantly affect the temperature by absorbing the warmth and keeping it from leaving, which breaks down the HVAC system faster. An underlayment can help control this problem.
  • Conserves energy: Now, who doesn’t want a more affordable electric bill? Moisture can affect the temperature within your home, causing the HVAC to work harder than it should. Since moisture barriers act as a sealant, they will save you money in the long run.

Is Mold Under Flooring Dangerous?

Simply put, mold can be hazardous within your home because it causes health issues, which is the main reason why it is crucial to get rid of it. A simple misunderstanding is that mold causes lung cancer, but research shows that this is not the case unless someone is near a fungus called Aspergillus. This rare fungal infection can lead to liver cancer. However, mold can cause scarring in your lungs, called pulmonary fibrosis, or PF for short.

Mold may also trigger asthma attacks and create your sinuses to swell up and not settle down (also known as chronic sinusitis). If you have a weak immune system or long-term lung issue, then it can lead to worse off sicknesses, such as:

  • Pneumonia: Which inflames the air sacs by being filled with fluid or pus.
  • Pneumonitis: Your immune system attacks the lung cells, causing swelling.
  • Aspergillosis: An infection causing breathing problems and chest pain.

How To Clean Mold From Underneath Your Vinyl Floors

Mold usually thrives either under the right temperature, by oxygen, and with a food source (which is in some form of water), which is why you hear of many people putting the mold in vacuum-sealed bags, where no air is present. Sometimes, it may be out of your control if it is worse enough, which if this were the case, it would be best to call a professional.

However, if you want to DIY getting rid of mold under your vinyl floors, follow these steps. Remember that you may have to replace much of the flooring but still need to fix the issue and eliminate the cause to ensure it does not come back. Make sure you have the proper equipment to get rid of it completely.

TOOLS TO HAVE:

  • Gloves
  • Goggles
  • Respirator
  • Protective clothing and shoes (make sure it is long to not get on your skin)
  • An extra pair of clothes and shoes (for when you are done)
  • Plastic sheets
  • Large garbage bags
  • Disposable rags
  • Tape or nails and hammer
  • Box fan
  • Dehumidifier
  • Two large buckets
  • Spray bottle
  • Borax
  • Scrub brush or broom
  • Heat gun (optional)
  • Pry bar (optional)
  • Chemical stripper (optional)
  • Floor scraper (optional)

STEP 1: Remove All Furnishing

First, it is vital to place clean shoes in the room’s front door to ensure you are not tracking mold in the rest of your home and then removing all unaffected furniture out of the room. If small objects are affected, place them into garbage bags, seal them, and immediately remove the items.

For easily replaceable objects, throw them away, but with clothes, washable carpets, or personal items, put them in the sun and take care of them once everything is said and done.

STEP 2: Seal The Room From The House

Closing the room is where your plastic sheets come in handy. Hang them from the doors, secure them with nails or duct tape, and then open a window to allow air to circulate through the area. Place a fan in the window facing outward or put it on the floor facing towards the window. Ensure the fan does not blow directly to the moldy areas; otherwise, more spores will be released. 

STEP 3: Prying The Baseboards

Remove all baseboards where you know it is contaminated. If you are sure the mold is in one small area, you can pry those specific flooring sections plus an extra 1-2 feet more to make sure there is no other mold. Just be prepared to remove more planks if you see additional mold. 

STEP 4: Gently Strip The Flooring

As gently as you can, remove the flooring, starting with the edge of the room. Cut long slits under the vinyl flooring by sliding a scraper underneath and pulling them up as you scrape. If they are glued down, extra work would need to be put into place, whereas a floating or lock in place system will be more manageable. The planks that do not wish to bulge, apply heat with the heat gun or a chemical stripper to pull them up. 

If the boards are in good condition, you may treat the vinyl floors and reuse them, so make sure to pile them to one side until the subfloor is mold-free.

STEP 5: Mix Borax Solution

With 1 gallon of water, mix 1 cup of borax in a large bucket, fill the spray bottle with the solution and treat small affected areas. 

If it would be easier not to use a spray bottle, you can work directly out of the bucket by using a brush or broom, like paint. Then swab the mixture across the floor, waiting 10 to 15 minutes to let the water saturate the mold and weigh it down to keep the spores from going anywhere.

After this:

  • Scrub with a brush or broom before reapplying more of the blend.
  • Wait another 10 minutes.
  • Wash the last time.

Doing this several times means the mold has been ultimately killed off. 

STEP 6: Vacuuming

If possible, vacuum the subfloor with a HEPA vacuum to remove the bulk of dead mold. 

On the other hand, you can make another borax solution and rinse it over the floors multiple times by using a rag that is thrown away later. Make sure not to soak the area, as this may further create fungus on the subfloor. 

STEP 7: Spraying The Subfloor

With a light layer of borax water, spray the subflooring, which hinders mold from occurring again. Then, make sure it is shriveled before moving to the next step. Turn up the heat and put a dehumidifier in the room to provide faster service. Wait at least 48 hours to see if the subfloor is withered.

STEP 8: Replace The Flooring

Replacing the vinyl flooring is a must, as you should not be reusing moldy planks. Most warranties cover it, so make sure to reapply the clean or new trim before purchasing new floors. 

Lastly, remember to get the moldy items that were left outside to sundry, and treat them with the borax solution before bringing them inside.

Final Thought

Although mold can grow under vinyl plank flooring, it is crucial to detect the issue by looking in humid areas and noticing any change within your health, water bill, or coloring in any corners or crevices. Seeing it early on can help you create a simple solution before the mold affects the entire house, leading to an even larger issue than it should be. 

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.

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