What are the Signs of Mold Under Hardwood Floors?

Just uttering “mold” is enough to strike fear into the hearts of even the most experienced home-owner.

Ever noticed dark patches on your hardwood floors, or picked up a musty smell that you can’t shake off? Ever wondered why your floorboards are getting progressively creakier? You could be dealing with a silent invader – mold!

Let’s unearth the secrets of mold that may be tucked away under your floorboards!

What you’ll learn in this article:

  • The most common signs of mold under hardwood floors
  • Reasons behind mold growth
  • Ways you can prevent mold from growing

What are the signs of Mold Under Your Hardwood Floors?

There are various cues that might point to the presence of mold, including certain visual hints, health symptoms, a strange smell, and noticeable changes on the floor surface. Take note if you:

  • See discolored, darker patches popping up on your flooring that have a slimy or fuzzy texture
  • Smell a musty odor in the room. That happens because mold releases microbial volatile organic compounds as it sprouts and grows.
  • See flaking or peeling that could be a sign that moisture from mold is breaking down those adhesive bonds between your floor and its protective coating.
  • You might notice your floorboards are a bit more talkative, too, with all that creaking.
  • Other signs of trouble could be buckling or warping of your hardwood floors. Remember, this happens due to trapped moisture. This warping occurs when wood drinks up water and expands, causing the floor to curve. Often, this is accompanied by the wood floor cracking.
  • Don’t ignore any water stains, as these are often silent alerts to underlying water damage. 
  • Surface mold can sometimes be visible, often appearing black, white, or spotted—but it could be just about any color. Mold can seem powdery, cottony or even velvety to the touch. Discoloration or water stains on the flooring could also be a red flag, causing the wood to become lighter or, in the case of other porous wood types, darker. 

What is Mold? 

Mold – no one likes the sound of it, but what exactly is it? Simply put, mold is a sneaky type of fungal growth that likes to spread on damp or decaying organic matter. It multiplies by releasing tiny little things called spores into the air.

The culprit? Moisture. 

Here’s why you should be concerned; besides wreaking havoc on your beautiful hardwood floors, mold can pack a mean punch to your health too.

Mold can cause of serious health issues such as respiratory illnesses and even bring on hypersensitivity reactions in certain individuals.

Why Does Mold Grow in Homes?

To understand how mold manages to colonize your hardwood floors, let’s delve into the conditions that become hotbeds for their growth.

The common denominator in all cases? Moisture. It could be a water leak you didn’t notice, condensation in your home, a high level of steam from your hot showers, or high humidity. 

If the humidity levels in your home are consistently above 60%, you’re risking mold, because the moisture stays in the air way longer, perfect for mold to set up shop.

What Types of Mold Typically Affect Hardwood Floors?

Not all molds are created equal. Some types have a particular fondness for your hardwood floors. Among these, Chaetomium is the most common.

It’s the most common type of mold found springing up on wood floors and can even produce mycotoxins – nasty substances you definitely don’t want around. 

What Health Risks Are Associated With Mold Under Hardwood Floors?

A lot of folks aren’t aware that these visible signs or symptoms might actually be a signal that mold is festering under their hardwood floors.

Ever experienced ongoing respiratory issues or irritating skin rashes? What about a stuffy nose that just won’t quit, wheezing like you’ve run a marathon without even leaving the house, or itchy eyes that seem to always be irritated? It’s possible that these issues could be a sign of mold exposure. 

Molds are crafty and can produce allergens that often lead to allergic reactions. So, if you’ve recently had an increase in these symptoms, it might be high time you checked for potential mold under your hardwood flooring.

How Can Mold Damage my Hardwood Floors?

With a mold infestation under your hardwood, you’re not just looking at potential health risks. Your floors themselves are also at risk.

Mold can cause visible warping, a sign that the fungi have made home within your hardwood. This warping typically happens when water spills onto the floor and, after evaporating, leaves the fungi to cling onto the hardwood. Over time, the wood starts to unnaturally expand. 

You might also notice cupping – this is when the edge of the plank rises, giving your floor a wavy look. Crowning is another issue where the middle area of the hardwood floor rises above the rest.

The worst-case scenario is buckling, where the hardwood floor pulls up from the subfloor by several inches.

The sooner you act, the better for you and your lovely hardwood floors.

How do you Prevent Mold Growth Under Hardwood Floors?

If you do notice some of these signs of mold, here are some precautions you can take:

  • First, and foremost, you have to address the primary cause of the mold which is the moisture, leaks, or humidity.
  • Air your rooms regularly. Yes, let the air flow! Open your windows and doors for simpler air ventilation. It sounds too simple to be effective, but good airflow can fight off many evils, including mold. 
  • If you feel the need to take it up a notch and you’ve got a fan lying around, position it at the window and have it point outwards. This creates a nice little air exchange, which works great in reducing moisture and humidity levels indoors.
  • As you might have gathered, mold can be really harmful. So, while you’re on this mission, remember to protect yourself. Use gloves, goggles, and an N-95 mask during the mold removal process. Trust me, these aren’t “nice-to-haves”, they’re a must!
  • If it’s really bad, you might need to call in a pro to fix the issue. Bringing in professional help can make all the difference- they’re trained to handle things like this after all. 
Picture of Tom Powell

Tom Powell

Over the last 7 years, I’ve done a bit of everything when it comes to maintaining and repairing my 110-year-old house. Installed vinyl plank and vinyl peel and stick flooring, resurfaced and stained wooden porch, leveled and installed tiling on a concrete floor, resurfaced our kitchen cabinets… It never ends, but it feels great when you finish a project yourself and end up with a beautiful new (or repaired) floor.

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Picture of Tom Powell

Tom Powell

Over the last 7 years, I’ve done a bit of everything when it comes to maintaining and repairing my 110-year-old house. Installed vinyl plank and vinyl peel and stick flooring, resurfaced and stained wooden porch, leveled and installed tiling on a concrete floor, resurfaced our kitchen cabinets… It never ends, but it feels great when you finish a project yourself and end up with a beautiful new (or repaired) floor.

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