The Unfortunate Signs of Mold Under Vinyl Flooring

If your house smells musty, or you notice discoloration on your flooring, you may have mold under your vinyl flooring. Mold seldom remains hidden for long, so if you see mold creeping up from under your vinyl flooring–you’re probably looking at a much bigger problem. Mold is extremely toxic, so professional testing and removal is almost always required. 

Why is Mold Trapped Under Vinyl Flooring Dangerous? 

People are terrified of discovering mold, and for good reason. Once it takes hold it can spread rapidly, causing serious health complications (especially for those with compromised immune systems), and can wreak havoc on the structural parts of your house. 

When it comes to vinyl flooring, the minute you discover mold underneath it, that flooring is now garbage. Mold is stubborn and can grow from even the tiniest spore. Anything relatively cheap—like vinyl flooring—that is infected with mold should be discarded appropriately, as soon as possible. If you’re wondering whether or not you need a mold inspection, the answer is a resounding yes. 

Health Risks

There are many types of mold and, unsurprisingly, none of them are good for you. Black mold is one of the more common varieties, and is one of the most toxic. Mold poisoning symptoms include, but are not limited to:

• Shortness of breath

• Brain fog

• Respiratory distress, such as a persistent cough or phlegm 

• Migraine 

• Runny or stuffy nose 

• Eye and skin irritation 

• Fatigue. 

• Gastrointestinal (GI) issues

If you experience any of these issues, and notice mold–either from sight or smell–visit a doctor immediately. In more serious cases, consider a hospital visit. These issues can develop very suddenly, or they could build over time. 

Structural Damage

Mold has a corrosive effect on the surfaces it inhabits. Mold feeds on moisture, and while you may think your wooden cabinets or vinyl flooring is dry, there is enough moisture present for mold to grow. This is especially true for vinyl flooring, which has a tendency to “gap” between the flooring and the base floor it’s placed on. 

Once the mold spreads, that’s an easy write-off for your vinyl flooring. However, it can also damage the underlying structure. Vinyl flooring is commonly placed over old hardwood, and mold will, over time, eat through the wood. 

Ideally, you will find this problem early, but vinyl flooring does a good job of masking mold growth. Mold is like cockroaches—if you see any signs or even one, it’s safe to assume there’s more. 

Signs of Mold Under Vinyl Flooring

Photo: Nicolas St-Germain / Adobe Stock

Smell

Mold smells. If you notice a musty smell in a room with vinyl flooring, that’s a dead giveaway that there’s growth under the flooring. While this isn’t good news, vinyl is easy to check under and rarely requires more than lifting a corner to check. Mold can also smell earthy (like mushrooms) or like rotting or decaying wood. 

Appearance 

There are a few signs mold is growing underneath your vinyl. Unfortunately, once you notice these signs, it means there is already a good amount of mold underneath. The only sign where this isn’t the case is when there are mold lines along the edge of the vinyl, as the mold may simply be growing in the space between the flooring and the wall. 

Other visible clues that—probably—indicate mold growth under your vinyl are:

• Irregular bumps in the surface

• Dark, splotchy patches that don’t clean off 

• A border of mold along the edge of the vinyl 

• Mold growing on the wall directly above the flooring

• Seams opening

• Adhesive deteriorating

Replacing and Repairing Mold-Damaged Vinyl Flooring

If the damage under your vinyl flooring was simply water damage, replacing it would be much easier. However, because you’re dealing with a toxic agent, you’ll need to call a mold inspector near you. 

Replacing and repairing should be done by a pro. Separating replacement and repair is a bit of a misnomer because, usually, they are one and the same. You can’t really repair vinyl flooring once it’s been tainted by mold, and it will need to be removed in its entirety. 

Professional mold removal costs between $1,100 and $3,300. This may seem high, but remember it isn’t just your floor that’s at risk—your health is far more important than saving a few bucks. 

Prevention Tactics

Preventing mold growth under your vinyl flooring isn’t as easy as preventing it from growing, say, under a kitchen cabinet. Mold needs moisture to grow, and it’s much harder to control moisture between two layers of flooring.

Your best bet would be to keep the humidity as close to 30% in your house as you can, and not higher. The reason for this is that mold likes to grow at humidity levels over 50%. Dehumidifiers and regular room ventilation are the two most powerful ways to prevent mold under your vinyl.

Other than preventative measures, react to any water issues immediately. Leaky pipes, water coming in through gaps, and any other water spills or pools need to be fixed as soon as you see them. A final step would be to conduct periodic mold inspections with a pro.