How To Remove Mold From Attic Plywood

How to Remove Mold From Attic Plywood

Attics are arguably the most susceptible to mold because of roof leaks, poor air sealing, and ventilation issues.

However, getting rid of attic mold, especially when it grows on plywood, is a tricky endeavor that most homeowners aren’t equipped to handle. Attic mold can impact indoor air quality and your family’s health, making its removal a top priority.

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This article will outline everything you need to know about removing mold from your attic plywood and how to go about it safely and efficiently. Let’s dive in.

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Signs of Attic Mold

Signs of Attic Mold

Routinely checking your attic for signs of mold will allow you to identify any problems and avoid panic scenarios. With that said, you’ll still need to know exactly what signs to look for.

Dark Staining

If your attic plywood has dark stains or black discolorations where it’s clear that the problem has moved beyond just moisture, it’s probably mold.

Hot and Stuffy Attic

Ideally, your attic should be cool and well-ventilated. If it’s starting to feel stuffy and hot, that’s a sign of poor ventilation, which frequently causes mold.

Frost Buildup on Roof Sheathing

During the winter, improper ventilation can cause water vapor underneath your roof to freeze. In time, this frost buildup will cause mold.

The Smell of Mildew

If you’ve got a sharp nose, you’ll likely be able to smell musty or moldy surfaces in your attic. Trust your instincts and spot these out. Read our detailed post more information on what mold smells like.

Wet Insulation

If your attic insulation is getting damp, it’s a surefire sign that your attic is far too moist and mold might already exist. It also damages the insulation, increasing the chance of mold in the future.

What Causes Attic Mold?

What Causes Attic Mold

Generally speaking, if you have a mold problem, you most likely have a moisture problem. If your attic plywood is accruing mold, you first need to address the moisture in your attic.

This issue is often caused by poor ventilation, air leakages, and roof leaks.

Blocked Ventilation

Attics usually have a passive ventilation system that lets outside air come through soffit vents and then leaves through the can or ridge vents on the top of the roof.

However, if one of these mechanisms becomes blocked, it disrupts the entire system. Warm air stagnates in the attic, then condenses with the cold wood sheathings in the attic. This creates moisture, leading to mold.

Air Leaks

In leaky homes, the air that’s driven by exhaust fans or the wind can blow through ceilings and attic floors. Because this air often contains water vapor, large-scale air leaks can cause condensation, which leads to mold on your attic plywood.

Roof Leaks

Roof leaks will cause mold to form in specific areas of your attic. Check for any wood discoloration and roof valleys. Roof leaks typically occur in chimneys, vents, or anywhere else in which dissimilar materials join together.

How to Remove Mold from Attic Plywood

How to Remove Mold from Attic Plywood

Removing mold from your attic plywood is not a simple weekend DIY job. Although you can certainly do it yourself if you’re willing to put in the manhours and purchase the equipment, we recommend contacting professionals to do it unless it’s only a few pieces of plywood that have mold.

For Small Removal Projects – Use a Wet Vacuum or Spray

If you have mold on your attic plywood in small areas, you can remove it yourself so long as it’s collecting in a small area (up to 10 square feet).

Mold Removal Safety Precautions

If you have to remove mold concentrations or perform any black mold removal covering more than a few square feet, we recommend you take these precautions:

  • Wear old clothes and shoes that you can launder or throw away after the cleanup work.
  • Wear special N-95 or P-100 respirators, in addition to goggles and gloves.
  • Set an old box fan or a cheap new one in a window to ventilate the room while working.
  • Wrap and tape moldy contaminants in 6-mm plastic, and double-bag mold-infested debris in garbage bags for disposal.
  • To control airborne spores, moisten moldy areas with a garden sprayer while you work.

You can get rid of mold-contaminated wooden surfaces using a wet vacuum that can fill its tank partially with water to control mold residue. Wipe the surface with a damp sponge or cloth that’s been treated with clean water or wood cleaner.

Once the surfaces have been thoroughly dried, use a HEPA vacuum cleaner on the plywood and safely dispose of all the contents by putting them in well-sealed plastic bags. Any contaminated material, including mold-infested insulation, should be sealed in plastic and disposed of as regular waste.

Hepa Vac for Attic Mold Removal

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Beyond using this vacuum to remove mold from your attic, you’ll find it convenient for cleaning floors, curtains and other areas that collect a lot dust and debris on a day to day basis.

If you have attic mold in multiple areas and it exceeds 10 square feet, we recommend that you contact a mold remediation company to take a look at your attic and decide the best course of action.

For Larger Removal Projects – Hire a Professional Mold Remediation Company

It goes without saying that attic mold removal is no walk in the park for any homeowner. Not only does the possibility of falling through the attic floor make it an extremely dangerous undertaking, but you’ll also need to purchase plenty of expensive equipment to pull it off.

Attic mold removal is therefore borderline impractical for homeowners, even those with plenty of DIY experience because of the dangers it presents. Even if you manage to do it safely, there’s no guarantee that you covered all the bases given all the variables.

Because mold presents serious health concerns while also damaging your home’s overall energy efficiency, we believe this is a job you shouldn’t have to gamble on. If you hire a professional, you can give you and your family peace of mind knowing that the mold was assessed correctly and removed from your attic plywood using the right methods.

How to Remove Mold Stains in Attic

Once you’ve effectively removed the mold from your attic plywood, you may want to remove the unsightly stains left behind.

There are a number of different mold removal products out on the market that you can use and apply to remove even the most stubborn stains in just seconds.

RMR-86 Attic Mold Stain Remover


If you’re looking for an extra strong mold stain removal solution, we recommend using RMR-86 Pro Instant Mold Stain & Mildew Stain Remover. This is a staple for contractors and is safe to use on a number of surfaces including attics, crawl spaces, wood, drywall, and more.

RMR-86 uses an ultra strong formula that instantly dissolves difficult mold and mildew stains without scrubbing or sanding to get the job done quickly and efficiently, saving you both time and money.

Read our full RMR-86 Mold Remover Review.

How to Prevent Attic Mold

How to Prevent Attic Mold

Once you’ve removed mold from your attic, you’ll still need to take care of the root cause if you want to keep it out of your home. In this section, we’ll be exploring how to properly air seal and ventilate your attic to keep it cool and dry.

Air Seal

When air sealing your attic, it’s best to cover up the big holes before caulking smaller spots. For information on the best caulk products for air sealing, check out this post.

You can fill large gaps by placing a 16-inch piece of fiberglass insulation and place it in a 13-gallon plastic bag. Fold the bag once and place it in an open stud cavity. To find the cavity, you’ll need to dig through some insulation in your attic floor.

Need help indentifying air leaks in your attic? Schedule a free attic inspection.

Once you’ve filled the cavities with the insulation bag, place foil insulation over top. Cover it back with the insulation you removed earlier.

Plumbing pipes and small openings for wires are tiny areas that still leak plenty of air in your attic. Seal these holes stuffing small pieces of fiberglass insulation and cover them with expanding foam insulation. Electrical junction boxes can leak air as well, which you can easily plug with caulk.

Add Ventilation

Another major step to prevent mold growth in your attic is to make sure you have enough ventilation. Passive ventilation methods helps prevent humid air from getting trapped in your attic and wreaking havoc with mold growth.

With that being said, passive ventilation systems may not be enough. Homeowners should consider adding active ventilation, such as an attic fan, to provide continuous airflow. This will help remove hot humid air that enters your attic throughout the year.


Removing mold from your attic plywood is a step towards a cleaner, safer, and more energy-efficient home. When dealing with serious mold problems, bring in a professional indoor air quality (IAQ) consultant or mold remediation contractors. Don’t leave it to chance.

And remember — after removal, be sure to get to the source of the problem. Schedule an attic inspection and learn how to make your attic more healthy and energy-efficient.