Mold in Your Attic? How to Remove and Prevent It!

Discovering mold among the old dusty boxes in the attic is quite an unpleasant find. You and your family could have been breathing in mold-ridden air all this time. How do you remediate a mold problem in the attic and prevent its recurrence?

To remove mold in the attic, you can rely on household cleaners such as hydrogen peroxide, baking soda, and white vinegar. Natural remedies like tea tree oil also work. To prevent recurring attic mold, keep the area ventilated and fix roof leaks when they start.

In this guide, you’ll learn everything you need to know to ameliorate a growing mold problem in your attic. This is for the health of you and your family, so it’s worth doing, whether that’s by yourself or by hiring the pros.

Remove mold in attic

What Does Mold in Your Attic Look Like?  

The following signs indicate a likely mold issue.

Splotchy Patterns on attic plywood

As we’ll discuss further in the next section, water leaks are a common culprit of mold in the attic. The mold will grow where the water permeated through the walls, developing a splotchy pattern on beams and attic plywood.

White and green mold appear the most frequently in an attic, but black mold is a possibility as well.

If it is indeed black mold, it tends to develop in more than splotches, but in crescents or circles. These aren’t vaguely circular-shaped patterns, but perfect circles.

The more perfect the circle, the more serious the mold problem.

Colored Areas

You might not know your attic plywood walls innately well, but you can ascertain the difference between colorful spots and the rest of the wall.

After all, mold isn’t solely green, white, or black. It can also appear as white, orange, yellow, or pink areas on the wall. These colors are a clear giveaway that the attic has become a hotbed for fungus.

A damp and “musty” smell

Before you notice any visible signs of mold in your attic, you may well smell them first. An obvious sign of mold build-up is a strong musty odor. The smell can often be described as being similar to the smell of rotting wood, or damp soil.

What Causes Mold in the Attic?

You’ve identified what you believe is mold in your attic. Before you can treat the issue, you have to understand where it stems from. Otherwise, the treatment will only work short-term before the mold regrows.

Here are some causes of mold growth in the attic to be aware of.

Lack of Ventilation

Attics should have some form of ventilation, not solely as a mold preventative, but to enhance the heating and cooling capacities of your home’s HVAC or ductless system.

Whether ventilation was omitted during the construction of the attic or time and decay have caused the ventilation to weaken, the stagnant environment is perfect for mold to propagate. That’s especially truest in the summer when the attic will be warm, stale, and moist.

Bathroom and Kitchen Exhausts

Depending on the layout of your home, exhausts from humid areas of the house such as the bathroom or kitchen could be redirected to the attic.

If the attic is well-ventilated, then the exhausts can pass through the space without necessarily causing or worsening a mold problem.

However, poor ventilation or a lack of ventilation gives the exhausts nowhere to exit. The hot air lingers in the attic, perpetuating the mold issue. 

Roof Damage

Roof damage mold

Some homeowners delay roof repairs due to the expense associated with this project, yet this can be a costly mistake for one’s health.

Small roof leaks that you ignore can easily become bigger. The water from the roof will directly enter the attic.

The moisture has no place to exit, so it’s only a matter of time before mold develops.

Areas of the roof such as flashings, windows, chimneys, fascia boards, sheathing, and rafters can become discolored through leaks, as can any roof insulation. That’s a sign that the problem afoot is serious.

Condensation buildup

Newbuild homes are often built with insulation being a major factor to ensure the property is as energy efficient as possible. Whilst this is certainly a good thing for energy consumption levels, it poses a greater risk of condensation building due to moist damp air being trapped in the home.

This air will often condensate on the coolest parts of the home, so you’ll often find droplets of water on your windows or walls. However, these water droplets can find their way into your loft or attic space, where they can settle and condensate, creating the perfect environment for mold and mildew buildup.

Ensuring your home has the proper ventilation required to allow air to escape when needed is vital to prevent a large amount of condensation, and therefore, potential mold to accumulate.

How Long Does It Take Mold to Grow in an Attic?

If a mold problem in your attic seems like it sprung up out of nowhere, that’s likely because it did.

Warm and wet areas such as the attic can begin growing visible mold in as little as 24 hours and as long as 48 hours.

On hard surfaces, it could take between two and three weeks for the spores to be visible, but they are indeed there. Mold spores will usually start to become visible between 18-24 days.

How to Remove Mold in Your Attic

Find the source

Before we begin to discuss the various methods of removing mold from your attic, it is important to note that you must first ensure that you have found the source of the moisture that is building up in your attic.

Mold cannot form without moisture, so it is advisable to thoroughly check all roof tiles (for cracks/gaps), vents (for any blockages), and any other potential source of moisture into the attic. Without addressing this, even after cleaning, you may well find yourself back in the same position in a few months’ time.

The following household cleaning products can remove mold spores on the attic walls and other surfaces. Do keep in mind that without remediating the causes of the mold that it will come back.

Hydrogen Peroxide

The first household product you can use to treat attic mold is hydrogen peroxide.

The concentration only needs to be three percent, which is the type of hydrogen peroxide most commonly available at pharmacies and grocery stores.

  1. Transfer 3% hydrogen peroxide into a spray bottle for an even application. Mist the affected areas of the attic with the cleaner and be sure to fully saturate them.
  2. Allow 10 to 15 minutes to elapse. The hydrogen peroxide is likely to begin bubbling, which is a sign it’s combatting the mold.
  3. With a soft brush or a rag, remove the remaining mold from the walls. You’ll need a wet cloth to clear the hydrogen peroxide residue.
  4. Dry the attic surface with a clean cloth, as a wet surface could attract more mold.

Baking Soda

Next, baking soda is a nontoxic method of attic mold removal. It’s even effective on black mold.

Baking soda will absorb the moisture in the attic so the room is less likely to attract mold.

  1. Combine water with a quarter-tablespoon of baking soda. Shake the ingredients until you don’t see any powder in the spray bottle.
  2. Spray the affected areas of the attic and use a scrub brush to lift the mold from the wall or ceiling.
  3. Use a wet soft cloth to remove any lingering baking soda and then pat the area dry with a clean cloth.

How to Naturally Remove Mold in the Attic

For those who are looking for more natural mold removal options for the attic, here are three products to try.

Tea Tree Oil

Although tea tree oil has a rather strong scent, this natural mold remover is safe to breathe in.

Before purchasing tea tree oil, double-check that it contains Melaleuca Alternifolia, which means the product is made from real tea tree.

Dilute a teaspoon of the oil with a cup of water and pour the mixture into a spray bottle. Cover the moldy wall or ceiling with the tea tree oil and leave it to work.

There’s no need to remove the tea tree oil from the wall, as it won’t cause the attic any harm. The smell should fade eventually.

White Vinegar

The next natural cleaner at your disposal for attic mold removal is white vinegar, a disinfectant, and a deodorizer.

White vinegar is effective on nonporous and porous surfaces alike, so no matter which comprises your attic, this household cleaner is handy to have.

  1. Pour the vinegar straight into a spray bottle and don’t dilute it with water.
  2. Spray the affected areas generously and allow the white vinegar to work for at least 60 minutes.
  3. Come back into the attic, clean the area with water, and dry the wall or ceiling. If the attic is ventilated enough, the vinegar smell will dissipate within the same day.

Rubbing Alcohol

Isopropyl alcohol, more commonly known as rubbing alcohol, is a suitable natural mold remover.

It’s not quite as effective as white vinegar, tea tree oil, or the solutions in the last section, so several applications may be needed.

  1. Combine an equal ratio of water to rubbing alcohol in a spray bottle.
  2. Coat the moldy attic wall in the mixture and allow it to work for 15 minutes.
  3. Wipe away the mold with a sponge or scrubber and then rinse the rubbing alcohol residue.
  4. Dry the surface with a clean cloth.

Can You Paint Over Mold In Your Attic?

Mold is visually unappealing, so you might feel a strong inclination to paint over the moldy walls or ceiling of your attic.

While painting visually reduces the appearance of mold, it does nothing to remove the mold itself. The fungus is still there underneath the surface.

If the mold continues to spread­–which is likely if the attic remains poorly ventilated and moist–then the next strains of the mold may grow atop the recently painted wall.

This can create a vicious cycle of repeatedly painting the wall but not getting anywhere with the mold problem.

Even mold-resistant paint is not a solution. The formula in these types of products is designed to prevent mold after the fact but will not treat existing mold.

Is Mold in Your Attic Dangerous? Can it Make You Sick?

Mold in the attic is risky from more than an aesthetics standpoint, but for the health of you and your family as well.

The spores that start in the attic do not necessarily stay there. They can filter throughout the house, spreading to the upper and lower levels.

Mold in the attic can make you and other family members sick in the following ways.


Affecting “one in five people,” according to the Cleveland Clinic, mold allergy sufferers will find that their symptoms become much more severe when a mold problem in the attic worsens.

Those symptoms can include a skin rash, headaches, sneezing, coughing, itchy eyes or throat, wheezing, nasal congestion, or a runny nose. 


Asthma can be worsened by many things, including cold air, exercise, respiratory infections, pet dander, dust mites, pollen, and mold spores.

Those in your home with asthma will find it especially difficult to breathe and may need to use their inhaler or asthma medication more often.

Respiratory Distress

Even those family members with perfectly healthy lungs could be impacted by the presence of mold if they breathe it in for long enough.

Mold could possibly cause headaches, weakened immunity, and respiratory distress in those with healthy lungs.

Further, according to Healthline, long-term mold exposure could lead to asthma diagnoses in previously healthy children, mold allergy diagnoses, fatigue, sinusitis that won’t go away, and even Legionnaire’s disease, a type of pneumonia.

White Attic Mold Removal

Going back to our point from before, white mold is one of the more commonly sighted types of mold that appears in attics. It’s splotchy, fuzzy, and requires immediate removal. The most common forms of white mold found are Aspergillus, Penicillium, and Cladosporium.

Baking soda, white vinegar, and hydrogen peroxide are the three top products for treating white mold in the attic.

Attic Mold Removal Costs

For those homeowners considering entrusting a professional to remove mold in the attic, one of the first questions they’ll have is about the cost of such a service.

Per data from HomeGuide, the price of a professional mold removal service is between $1,500 and $3,150, with $2,325 the national average.

The hourly rate that most professionals charge is between $75 and $108. How many hours the professionals would have to work depends on the extent of the mold damage.

Should You Remove Mold from Your Attic Yourself or Hire a Professional?

After reviewing the costs of professional mold remediation, you may be leaning more towards DIY or sticking with the pros.

Both have their advantages, but which is the best decision comes down to several factors.

For example, how severe is the mold problem? What’s causing the mold problem and is that easily fixed?

Has the mold spread to other areas of the home? Is it beyond the walls and into the wall insulation?

You can treat surface-area attic mold yourself, but if the fungus has gotten inside the walls, that could be completely unbeknownst to you.

The mold problem will persist even though the surface mold is gone.

If you suspect that your mold problem extends beyond what you can see, or if you’re dealing with rampant black mold, your best course of action is to hire professionals to remediate the mold.

Although this is a costly endeavor, you’ll have the peace of mind that your attic is truly clear of mold.

The Best Products for DIY Attic Mold Removal

Should you opt for a DIY removal because your attic mold problem isn’t overly extensive, you cannot solely rely on the household cleaners or natural products we recommended earlier.

These products only remove mold but do not kill it, after all.

The following DIY-friendly mold removal products will more effectively eradicate mold from the attic.

CLR Mold & Mildew Stain Remover Spray

CLR’s spray works against mold and mildew, but we recommend it the most for your purposes because it’s usable on a variety of surfaces. These include glass, painted walls, brick, concrete, fiberglass, wood, and fabric.

Whether your attic walls are finished or unfinished, this CLR foam spray will quickly treat mold and the stains it can leave behind.

The Environmental Protection Agency or EPA added the CLR Mold & Mildew Stain Remover Spray to its Safer Choice Program as a product that’s safe to use around the house.

RMR-86 Pro Instant Mold Stain Remover

Another mold/mildew product, RMR-86 Pro can penetrate deep into the surface to lift mold when other cleaners haven’t done so successfully. The main ingredient in this mold remover is sodium hypochlorite.

Recommended for decks, drywall, plywood, brick, concrete, and wood as well as crawlspaces and attics specifically, this is another product that won’t leave a lasting mess in the attic.

How to prevent mold in your attic

Rather than waiting for mold to form in your attic, you have the option of preventing it from occurring in the first place. And if you have already found yourself tackling the problem and don’t want to again, you’d best make sure you have all the preventative measures in place.

With that being said, here are a few options to make sure you don’t have to deal with this problem again, or never do in the first place.

1. Ensure you have adequate ventilation

Making sure your attic is adequately ventilated is one of the best ways you can prevent mold. Soffit, roof, and gable vents are an excellent way to naturally allow air to flow (known as passive ventilation) through your attic, preventing moisture from pooling, condensing, and eventually forming mold.

Positive pressure ventilation is another method of creating airflow through your entire property, even in almost air-tight new-build properties. A unit is placed within your attic and draws air in through filters, it is then passed under pressure through vents in the ceiling to create additional air pressure in your property, which forces warm moisture-laden air out of your home.

2. Ensure all ventilation pipework (ducting), is properly insulated

A common cause of moisture buildup in your attic is water condensing on ductwork from air conditioning and ventilation systems. Ensuring all ductwork is appropriately insulated will help to lessen the opportunity for condensation to occur, making it much less likely for mold and mildew to form.

3. Keep the moisture level in your home between 30-50%

The optimal moisture level for mold to grow is 55%, so keeping your home under this level is a great preventative measure. Bathroom and kitchen extractor fans can help to remove moisture from bathing and cooking, as well as running a dehumidifier if the moisture levels become overly high.

Drying clothes outside (if possible) is an easy way to lower moisture levels, and if that is not possible, use a tumble dryer to exhaust moisture outside of the property.

Is Mold in the Attic Common?

Given that attics are small spaces with barely-there insulation, they’re one of the most attractive parts of the home for mold to grow. The basement is another source of mold growth, and the bathroom sees its fair share of fungi as well. 

As a result of this, finding mold in your attic should not come as a surprise if the necessary steps are not taken, as mold accumulating in an attic space is a very common occurrence.

One of the main factors that determine whether mold and mildew can formulate is the property’s insulation. A property needs to “breathe” to allow the warm moist air found in homes to escape.

Poorly fitted insulation will allow the moist air into the attic, where it has the opportunity to settle and create mold spores. If the appropriate quality insulation is properly fitted, and there is adequate ventilation, mold should not be able to accumulate.

Newbuilds often have an abundance of insulation that creates excess condensation which can lead to mold growth, whereas older properties are more likely to be poorly insulated, leading to warm and moist attic environments.

For these reasons, it is very common to find mold growth in both new and old properties.

Do Fans Help with Attic Mold?

While you may plan to reventilate the attic, that’s a time-consuming, pricy project for a little later down the line.

In the meantime, adding an oscillating fan or two to the attic can make a big difference.

The fans introduce what most attics sorely lack, and that’s air circulation. The air won’t linger heavy and moist, introducing conditions for mold.

Mold could still possibly develop in an attic with only fans and not a ventilation system, but it would be a lot harder for it to happen.


Mold in the attic is a common occurrence, but it’s one that shouldn’t be ignored. The presence of mold can worsen allergies and asthma and even infect healthy lungs, especially over the long term.

Chris Walker

Chris Walker has struggled for several years with mold after buying his own property. After finding the solutions to several issues around his home, he decided to create this site in order to answer as many questions about mold and mildew as possible to help others dealing with the same problems.

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