The Main Causes of Black Mold in the Attic and Methods of Its Removal

Leaks through the roof, condensation, ambient moisture and excess moisture, and poor air circulation can lead to black mold growth in the attic.

The attic is the ideal environment for mold growth. Homeowners in hot, humid areas frequently experience this issue. The majority of the time, homeowners seldom ever walk up to the attic and discover this issue only after selling or purchasing a new property. Many householders aren’t even aware that the rafter system is being slowly eaten away by a toxic, cancerous abode that is perched directly over their heads.

Signs of Attic Mold

The most obvious sign of attic mold is a musty odor. This smell comes from mold spores in the air, and it’s usually strongest in the attic. Other indications of mold growth in the attic are discoloration on walls or ceilings, and visible mold.

Dark Stains on Attic Plywood

Moisture seeping into the attic through the roof can produce a damp atmosphere that encourages the growth of mold. If you see dark stains on your attic plywood, you must act quickly to keep the mold from spreading.

Mildew Smell in the Attic

Mildew is a type of fungus that can cause a musty smell. This odor is typically strongest in summer due to the higher humidity. If you detect a musty smell in your attic, you must take immediate steps to stop mold from growing.

Uncomfortable Room Temperature

One of the most common indications of black mold in the attic is an uncomfortable room temperature. Black mold will typically grow in a warm and humid atmosphere, so if your attic is extremely hot and stuffy, you may have a mold issue.

Frost on the Roof Sheathing

Another telltale sign of black mold in the attic is frost buildup on the roof sheathing. This is usually caused by when the warm air inside the attic meets the cold air outside, creating condensation. If you see frost on the roof sheathing, it’s likely a sign of black mold.

Water Drips from Smoke Detectors

Finally, water dripping from your smoke detectors could also be a sign of black mold in the attic. Black mold can cause condensation on the smoke detectors, which can lead to water dripping.


Although the causes of black mold in the home (including the attic) are widely known, preventing mold is sometimes very difficult. Still, here are the main reasons for a full picture of the black mold problem in the attic.

Ventilation Problems

Inadequate ventilation in the attic can lead to moisture buildup and establish an ideal atmosphere for mold to flourish. Make sure your attic is sufficiently ventilated to decrease the probability of mold growth.

Improper Bathroom or Kitchen Fan Exhaust

Bathroom and kitchen fans are built to remove moisture from the air. If they are not vented properly to the exterior, the moisture can accumulate in the attic and cause mold. Ensure your bathroom and kitchen fans are correctly vented to the outside to prevent mold growth.

Roof Issues That Trigger Mold in Your Attic

Leaks in the roof can produce moisture buildup in the attic and create the perfect environment for mold to thrive. Make certain your roof is in good condition and that all leaks are fixed to inhibit mold growth.

Removing Black Mold From Your Attic

As a homeowner, you will probably want to get rid of the infestation yourself. Yes, you can clean the infestation with a metal brush and treat it with any detergent that contains chlorine. However, if you don’t find the cause of the mold, there’s a good chance you’ll be wasting your time and money.

When the average person thinks of mold, the imagination pictures moldy bread or cheese. The human brain likes to store memories by association. WRONG! What we can see is actually the fruiting body or reproductive part of a moldy organism, it’s a seed. If we want to get rid of mold forever, we need to destroy the roots, which ARE the body of the mold organism itself. And they are invisible to the naked eye because they grow beneath the surface, just as (for example) the tap root of the dandelion grows beneath the surface of the Earth. To kill mold, you have to kill the roots.

Most companies fight mold by using only biocide. With these methods, they leave 95% of the spores and do not remove the roots. Then they apply a sealant, which really means painting the wood. This is a booby trap waiting to go off as the paint forms a vapor barrier and eventually peels off. Which also leaves the mold roots alive and well and waiting for moisture.

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Next, there are many methods of sanding. Companies that offer these methods will tell you that they peel off the mold roots. However, this is simply not true! Mold roots grow deep into the wood. If you really try to sand the wood that deep, you will end up damaging the roof structure.

On the other hand, some homeowners may not care about mold because they don’t consider their attic to be a living space in their home.

We don’t recommend thinking that way. Moisture and mold can spread to other parts of the home and even threaten its structural integrity.

Fortunately, getting rid of mold in the attic usually doesn’t require much construction work or expense. But in the event that the main cause of mold is the integrity of the roof of the house (for example, the technical standards were not met during construction), it is better to be sure to evaluate the roof and, if necessary, replace the roof or its components.

It is not recommended to treat this problem lightly and not solve it at all. The best way to get rid of mold in the attic – to contact a professional and experienced roofing company that will accurately determine the cause of mold. After all, it’s not enough to just get rid of mold, it’s crucial to find the source of the mold. Otherwise, everything will go back to normal.

After you find the cause of mold, of course, you can’t leave your attic like this. To remove lesions and evidence of mold, use a biocide in combination with a sporicide that penetrates well into porous surfaces. It is also ideal to fill the wood or floorboards with non-toxic mineral salt so that the existing roots absorb the salt, die off, and no new spores will appear.


  • First, find the source and cause of the mold;
  • Get rid of the stains;
  • Kill the roots of the mold;
  • Be sure to kill the spores (spores are the hardest part of fighting mold because they look like seeds and spread easily throughout the attic);
  • Eliminate the cause of the mold.

DIY Mold Removal

If you decide to take on the task of removing the mold from attic yourself, there are several methods you can use.

Method 1: Use a vacuum cleaner with a HEPA filter to remove the mold. This is the most effective way to remove the mold, as the HEPA filter will trap the mold spores and prevent them from spreading.

Method 2: Use a solution of bleach and water to kill the mold. This method is not as effective as the vacuum cleaner, but it can still be used to get rid of the mold.

Method 3: Use a fungicide to kill the mold. This is the most expensive option, but it is also the most effective.

Method 4: Use a combination of the above methods. This is the best option if you want to get rid of the mold quickly and effectively.

Hiring a Professional to Remove Mold

If you decide to hire a professional to remove the mold, there are a few tips you should keep in mind.

  • Make sure the company you hire is experienced and certified. Ask for references and make sure they have the proper licensing.
  • Ask for a detailed estimate of the cost of the job. Make sure you understand all the costs involved before you sign a contract.
  • Ask about the safety measures they will take to protect you and your family from the mold.
  • Ask about the methods they will use to remove the mold. Make sure they are using the most effective methods.
  • Ask about the warranty they offer. Make sure you understand the terms of the warranty before you sign a contract.

Removing mold from your attic can be a difficult and dangerous task. It is important to take the necessary precautions and use the right methods to ensure the job is done properly. Whether you decide to do it yourself or hire a professional, make sure you follow the tips above to ensure the job is done safely and effectively.


I enjoy acquiring knowledge and sharing it. I am a long-time health advisor and blogger for over 12 years. Understanding the dangers of black mold to people, I felt it necessary to share with readers the basics of fighting and preventing black mold in homes and other living spaces.

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