Attic Mold: The Best Methods for Treating and Removing Mold Growth

mold on attic

Image Via Mold Inspection and Test

Mold can be one of the most costly problems a homeowner deals with. Treating and removing mold can involve large-scale renovation and repair, and can quickly turn into a much longer project than originally anticipated.

Roof leaks, poor attic ventilation, and other problems can all lead to a build-up of excess moisture, which leads to mold growth. Not only does mold and moisture cause serious deterioration of home materials, but it can also pose serious health concerns.

Identify the Moisture Problem

In order to successfully remove mold growth, the moisture problem must be identified.

Look for the following common sources of moisture penetration:

1. Rule out roof leaks

Condensation is often misidentified as a roof leak. Before you start a roof repair project to prevent mold growth, double check that moisture is indeed coming through the area you think you need to repair.

2. Stop air infiltration

Limit the amount of air movement from bathrooms and kitchens. Excess condensation from these areas can quickly lead to mold growth.

3. Dry roof sheathing and rafters

If you plan on treating mold in the winter, you should plan on drying out the attic sheathing. If you don't have the time or option to allow the attic dry out naturally, you can use heaters or dehumidifiers. Drying out sheathing is necessary, as moisture can freeze on it, leading to a white coating. As temperatures fluctuate, it will begin to drip, and this is often misidentified as a roof leak.

4. Ensure attic ventilation

Proper attic ventilation can greatly reduce the chances of mold growth in the attic. Read more about how to properly calculate and achieve air circulation.

Learn more about attic ventilation:

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Mold Remediation 

removing mold from wall

Before any mold treatment plan can begin, the attic needs to be properly prepared to ensure the treatment can succeed and the spores remain contained. 

Whatever method of mold treatment you choose, the process for preparing the attic is almost always the same.

1. Seal the area

Sealing off the area with tape and plastic sheeting keeps mold spores from spreading around the house. Taking the time to properly seal the attic can greatly reduce the chance of having to treat another area of the home.

2. Use a wet vacuum

A wet vacuum will clear any standing water and vacuum up mold spores on the floor. Don’t ever use a dry vacuum to remove mold, as it launches mold into the air.

3. Kill the mold

Kill the mold with your chosen method, whether that’s dry ice blasting, fungicides, or natural treatments. Be thorough and detail-oriented with your method.

4. Clean the area thoroughly

Clean the attic after the treatment by vacuuming, sweeping, scrubbing, or any other method necessary. Closely inspect any materials you sealed in plastic bags before returning them to the attic.

5. Dry out the area

Dry out the attic again using fans, dehumidifiers, and heaters. If you don’t take the time to dry the attic out again, the treatment may not work as well as it should. 

Keep reading about how to prevent common roof problems:


man treating mold

Dry Ice Blasting

Dry ice blasting is best used to remove surface mold after the source of moisture penetration has been found. Dry ice blasting is particularly effective in removing mold from difficult-to-reach areas, such as tight spaces and gaps in framing. It’s a non-toxic, non-corrosive, and only slightly abrasive mold treatment technique. 

Here's how dry ice blasting works:

  • Dry ice blasting shoots extremely small, cold pellets against the mold to remove it from attic surfaces.
  • The thermal shock helps loosen the mold, and the flash of carbon dioxide gas lifts the mold from the surface.
  • The bonus of dry ice blasting is that it leaves no residual material to clean up.
The negative aspect of dry ice blasting is the cost. It’s a fairly expensive procedure that should be left to professional mold treatment specialists. 

Chemical Treatments

While chemical mold treatments can be slightly hazardous, the use of anti-microbial chemicals can be very effective, especially when combined with other treatment methods.

Some precautions about chemical treatments for mold:

  • Some biocides are considered pesticides and usually require an applicator’s license to use them.
  • Never use fungicides developed for outdoor use, as they can be toxic.
  • Chemical treatments often kill the mold but don’t remove it. You’ll have to remove the mold with a wet vacuum or another method to complete the removal.
It’s worth noting that some people dispute the success of chemical agents for mold treatment and argue that they may cause health concerns. The biggest concern is bleach, as it is effective, but should be used extremely carefully because of its corrosiveness and negative health concerns. 

Natural Treatments

There are natural treatments available for removing mold if you want to avoid harsh chemicals. Whatever method you choose, it’s critical that you control the situation as soon as possible. 

Start by cleaning out your attic. Tie off objects in bags and take them out on your lawn to dry out. Allow the attic to completely dry with the help of fans, heaters, or dehumidifiers, then address the mold situation.

If you know your mold is of the toxigenic variety, take precautions to limit your exposure. Wear a breathing mask, goggles, and rubber gloves.

How to clean mold using natural methods:

  • Tea tree oil and white vinegar are safe for wood treatments and have strong fungicidal properties.
  • Hydrogen peroxide is an even stronger natural cleaning agent. Mix 1 teaspoon of white vinegar or tea tree oil with 1 cup of water.
  • Scrub the infected areas with your natural cleaning solution of choice using a firm wire brush.
  • Once thoroughly cleaned, completely dry out the attic again.

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Costs of Mold Treatments

The cost of mold treatments will vary greatly depending on the size of the attic, which treatment method you choose, and the contractors in your area. 

Treatments & Products Cost
Dry Ice Blasting $276 per hour
Chemical Products $30 - $60
Natural Products $25 - $50
Swab Testing $200 - $300
Air Cell Testing $250 - $350
Average Overall Price $1,130 - 3,352
$2,415 is the national average for attic mold treatment. If the mold damage is extensive, it may be necessary to replace structural materials or buy specialized protective and disposal equipment. These factors will increase the overall cost.

Hire the Right Contractor for the Job

Once you’ve learned how to identify common areas of moisture penetration and you've chosen your preferred method of treating the mold, it’s time to contact an experienced mold remediation contractor.

Many roofing contractors who specialize in roof repair also provide attic ventilation and mold treatment services. Go to to browse a directory of highly qualified roofing contractors.

Before you sign with any contractor, get quotes from at least 2 - 3 companies to determine the average price for the service.

Bonus Tip: A qualified mold treatment contractor should also be an expert in moisture penetration. Ask about their roof repair service to thoroughly protect your attic from mold growth. 

Keep reading about how to hire an ideal contractor: 8 Tips for Hiring the Right Roofing Contractor