Q & A

How To Prevent Mold Under Vinyl Flooring – A Practical Guide

Vinyl flooring is susceptible to mould growth both on top and below. Mold is often unseen because it thrives in cool, damp regions that are out of sight. By the time you find it, the growth may have spread to the point that it is difficult and expensive to remove. Hence, the age-old concern: “how can I keep mould from growing under my vinyl flooring?”

Mold can’t grow under vinyl flooring if it’s well-maintained and kept dry. Mold can develop in damp environments after a major water leak, such as a burst pipe or a flood. Mold can also grow if there is a water leak somewhere, such as below the sink or the toilet. If you let water leak under your flooring or along your baseboards, mould will eventually grow.

With this background, let’s go deeper into the specifics of what causes vinyl flooring to mould and how to avoid it. Here, we’ll go over some methods for detecting mould under vinyl flooring and getting rid of it. As an added bonus, we’ll discuss why and how you should instal a moisture barrier before laying vinyl flooring. As an added bonus, we’ll discuss some of the dangers mould can pose to your family’s health at home.

Let’s get down to the business of preventing mould growth and extending the life of your vinyl flooring.

What Happens If Vinyl Flooring Gets Wet?

Depending on the installation method, vinyl flooring can be either bonded to the subfloor or “floating.” Water seeping under the boards weakens the glue bonding, causing the sides to lift and the middle to ‘bubble. Not only does it encourage the formation of mould, but it also weakens the vinyl, causing it to break down.

Can Mold Grow Under Vinyl Flooring?

Water won’t damage vinyl floors because that’s how they’re made. Mold and mildew can form if water sits in one spot for too long or if moisture seeps in through the floor’s crevices along the walls and baseboards.

How Do You Find Mold Under Vinyl Flooring?

A musty odour, which is commonly linked with mildew, is a common sign of a mould problem. Examining the wall for mould growth indicators like dark patches and/or paint degradation is the best method to be sure. There is a good risk that mould will grow not just under the flooring but also on the wall if moisture has managed to seep through the borders along the floorboards.

Remove the vinyl flooring carefully so as not to damage the subfloor. This may need to be done in more than one location. If mould is discovered beneath the flooring, further investigation of the subfloor is required. To do this, cut off squares of the suspect material and examine them with a flashlight and a hand mirror for mould. The entire floor will need to be checked, thus many squares will need to be removed.

Do You Need A Moisture Barrier Under Vinyl Flooring?

There is no requirement for a moisture barrier when laying vinyl flooring over a wood subfloor. However, cork or foam should be used as a subfloor before laying vinyl flooring over an existing surface like hardwood, laminate, or tile. This not only protects the floor from leaks and humidity but also adds cushioning, making the floor feel better to walk on.

In the event that vinyl plank is to be installed in the basement, I advise using a product called DMX (dimpled membranes) over concrete since it serves as a moisture, mould, sound, and heat barrier. Most membrane manufacturers stipulate that the vinyl plank be at least 5 mm thick.

How Do You Install A Moisture Barrier Under Vinyl Flooring?

The following are the 5 steps to installing a moisture barrier under vinyl flooring:

Leave an extra 2–3 inches along each side of the rolled-out moisture barrier to overlap against the wall.
Follow the manufacturer’s recommendations for overlapping rows of flooring, which can range from 3 to 8 inches.
Seal the seams along the length of the underlay with a moisture-resistant glue or Tuck Tape.
Make sure the seams of the moisture barrier overlap throughout the length of each row as you lay and seal the underlay for the whole floor.
After the new vinyl flooring and baseboard trim have been fitted, use a utility knife to cut away any excess material along the wall.
Even while you can “patch together” portions of moisture barrier to achieve the length you need, please keep in mind that you should try to restrict or avoid doing so as much as possible. An uneven floor might be the result of joining too many seams, which can cause underlay material to accumulate and raise the floor. A new moisture barrier should be used instead if at all possible.

How Can I Get Rid Of Mold Under My Vinyl Floor?

The following are 5 easy actions to take to eliminate mould from under vinyl flooring:

Put 2 tablespoons of bleach into 1 quart of warm water, stir, and spray the solution around the house.
Spraying the solution onto the mouldy section of vinyl flooring will destroy the spores and stop them from spreading through the air.
Wearing disposable rubber gloves, scrub the mouldy area thoroughly with a cleaning solution and a scrub brush. If required, reapply the bleach/water solution and scrub the floor again.
After washing, rinse the area with warm water and dry it off with a towel to get rid of any remaining mould.
You should give the whole place a good mopping. The mop head, towel, and clothes should all go into the washing machine, while the scrub brush should be washed in hot water and the rubber gloves should be thrown away.

How Do You Dry Water Under Vinyl Flooring?

Even if your home suffers a leak or flood, the vinyl flooring may be salvageable if you act quickly to remove the water. First, you might attempt to remove as much water as you can by sucking it out with a shop vac. Then, run a fan or heater in the room for a few days to dry it out.

You may need to remove the vinyl flooring if the water damage is severe enough to allow the concrete or wood subfloor to dry out entirely. Assuming the vinyl flooring was installed over a moisture barrier, the underlayment and flooring could both be reinstalled after drying.

Is Mold Under Vinyl Flooring Dangerous?

The presence of mould in your house is not only unpleasant but also potentially harmful. Mold is a major health risk, linked to asthma episodes, allergic reactions, and even lung damage. That’s why it’s so important to completely eradicate it from your home right away.

Dangerous chemical substances are released into the air as mould spores reproduce and develop. These trigger asthma attacks, itchy, watery eyes, sneezing, and coughing by releasing allergens, irritants, and poisons. If mould has “overrun” your home, it’s time to call in the experts.


Mold can grow under a vinyl floor if the floor is not properly maintained and kept dry. If there is a significant water leak, such as from a burst pipe or a flood, the water will seep through the floor and along the baseboards, creating an ideal environment for mould growth. Mold can grow in as little as 24 hours if there is a leak below the sink or the toilet. Because of the potential danger it poses to human health, mould should be eradicated as soon as it is discovered.

I hope you have success with the upcoming home improvements.



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