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How To Remove Mold on Plywood Subfloor

How To Remove Mold on Plywood Subfloor

The carpet, wood, or tile you walk on each day is hiding a secret. Almost all homes have multiple layers of flooring, of which the nice, smooth clean floor you walk on each day is only one part.

Most homes have at least two layers beneath the top layer of flooring. A middle layer called “underlayment” is thin padding that gives the top layer its smooth and consistent foundation.

Beneath that is a layer called “subflooring” which is often made of plywood, and it is highly susceptible to mold.

In this guide, we will walk through what mold is, how to know if you have subfloor mold, how to treat it, and how to know when you should just replace your floor.

What Is Mold?

Mold is a type of fungus that sprouts up wherever there is excess moisture or an organic compound in a state of decomposition. Its function is to break down dying things and turn them into the soil that new, living things can sprout out of.

There are thousands of types of this fungus, and they’re all essential to the functioning of the natural kingdom.

Is It Dangerous to My Health?

While mold is a natural and necessary part of the life cycle, you don’t want it in your house. It sprouts up easily, spreads fast, and can be difficult to keep permanently out of your home once it’s taken root.

Person Coughing Due To Mold

This fungus can cause adverse health effects in human beings. It can exacerbate allergy symptoms, it can cause irritation to the skin, nose, and eyes, and it can worsen asthma. For those suffering from respiratory conditions, it’s imperative that living spaces be pro-actively resistant to mold.

How Do You Know If You Have Subfloor Mold?

This particular fungus can be difficult to spot, given its propensity for growing in dark, cramped spaces. Crawl spaces, in between walls, within insulation, and in the subfloor — even if the contamination is out of sight, it can still affect your health.

Fungi release microscopic spores that drift through the air, or in the case of subfloor mold, up from the floor you walk on each day and into your lungs. Truly the only way to check for a spread in your subfloor is to tear up the flooring, with the help of a licensed professional of course, and visually inspect.

Treating a Plywood Subfloor

It’s one thing when there’s fungus contamination in plain sight on the side of an easily cleaned wall. It’s another when the mold has spread through a difficult to access, hard to clean area that you’re exposed to everyday. The only way to truly remediate a spread is to call in an expert. But if you’re interested in the DIY approach, follow these 6 steps:

1. Safety Precautions

This is the most important step in the process. You need to secure the area to ensure the mold won’t spread by cordoning off the affected area with heavy plastic sheeting, covering yourself head to toe, so your skin isn’t exposed, and creating a negative pressure environment in which all air is suctioned out of the workroom and out of doors, so the spores don’t spread throughout the house.

2. Remove and Inspect Baseboards

Carefully pull up the top layer of the floor as well as the underlayment. Any boards which were exposed to the fungal contamination need to be disposed of immediately.

3. Expose Subfloor

Once you’ve removed the top floor and underlayment, your subfloor will be exposed. Inspect the infected area, and assess how much work you’re capable of doing on your own.

4. Check Floor Joists

Floor joists are wood or steel beams that the subfloor rests on, the true “foundation” of the house. If the joists have been exposed, it may be impossible to remove them, so they must be scrubbed with a heavy-duty fungicide before relaying the subfloor.

5. Treat The Mold

The treatment process involves scrubbing the affected areas with fungicide or a strong soap, removing moisture from the room, and exposing the area to prolonged ventilation.

6. Repair or Replace Damaged Subflooring

Inevitably, you’re going to have pieces of flooring that are too far gone with mold-related damage. If you’re able to do so, purchase the necessary replacement materials and relay your three layers of flooring.

Read more: How to repair a water-damaged subfloor

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Call in the Pros

As you’ve seen from this labor-intensive walkthrough, mold remediation is no joke.

That’s why it’s a good idea to leave the job to the mold remediation experts at All Dry USA. Call today to get a quote, schedule an inspection, and get your house back to peak health.


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