How to Remove Mold in Your Barn

Reader Contribution by Megan Wild
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Mold can get into your barn either as part of the aftermath of heavy rains or a flood or because of chronic moisture conditions. If it does, it could endanger your health, plus the health of your family, any other people who work in or near the barn, and your livestock.

Why? Well, some molds contain mycotoxins and infectious airborne spores that are toxic. Other varieties can cause allergic reactions.

While mold is sometimes visible, bear in mind that sometimes you can’t see mold until it reaches a certain size. It is just as dangerous invisible as it is visible.

While danger is one negative aspect of mold, there are others, too. Left unchecked, it can cause severe damage to equipment and eventually compromise the structural integrity of your barn.

Mold needs certain moisture conditions to grow. That’s why you should be especially vigilant about mold after a flood or rain. Moisture conditions in your barn act as a breeding ground for mold. Any leaks in the plumbing or the roof, condensation from an air conditioner, or even high humidity inside the barn can create an environment where mold will thrive.

Even conditions of limited moisture can cause problems if the area doesn’t have sufficient air to dry out.

If you have mold in your barn, there are several steps to take to remove it.


1. Examine your barn for moisture. Where is the source? If you don’t fix the source of moisture, mold conditions will form all over again.

2. As the second line of prevention, you might want to call a mold remediation service. They have experience eliminating toxic mold and can test to see if you have invisible mold spores in the air. They will kill mold spores and stop them from reproducing.

3. Do not let your family or any workers inside the barn until all mold has been found and eliminated. Do not let them take any items from the barn either. Even grabbing a hammer for use in the garage can contaminate your garage and home as well. Mold grabs hold and breeds wherever it can. Moving items is essentially giving it a new home.

4. Never paint over mold. Don’t paint if you suspect you have mold not visible to the naked eye. Some paints advertise that they use a mildewcide, but they are not sufficient for eliminating mold. It will simply eat up the paint.


1. Find all the mold infestations you have. Making a map can be helpful. Look for the visible ones first. Then test for invisible mold.

2. Unfortunately, airborne mold can make its way into heating and cooling ducts. If you find you have an infestation of mold, it’s a good idea to replace your units. You can also run a mold fogging machine and use a fungicide approved by the Environmental Protection Agency (EPA).


1. Dry the area with dehumidifiers. Don’t use fans. The blowing from fans can spread mold spores through the barn and into any heating and cooling system if it isn’t already there.

2. Use a fan, however, to blow air outside the barn continuously. Using an industrial HEPA filter with a flexible hose to vent outside is a good idea.

3. Purchase protective gear. A full-face respirator mask is a must. It is also advisable to purchase biohazard suits. If you can’t do this, be sure to wear clothes that cover your body including long sleeve shirts, long pants, and gloves.

4. Purchase a mold fungicide registered with the EPA. Spray or fog it twice. No one but the person doing the spraying or fogging should ever be inside the barn while it is taking place.

5. Scrub off as much visible mold as you can from every surface and area. Use either Borax laundry detergent in warm water or trisodium phosphate (TSP).

6. Bleach is often recommended as a mold killer or disinfectant. However, it will not kill toxic mold or impede its growth. If you aren’t sure whether you have toxic mold or not, use the materials above. If you’re sure it isn’t toxic, you can scrub with a solution of one cup of bleach to one gallon of water.

7. If mold has infected your wood, scrub it off using Borax or TSP. Any beams, timbers, shelf surfaces, trusses, joists or other wood will need to be planed and sanded to remove the first layer, to make sure all the invisible mold is gone.

8. All cleaned areas need to be resprayed with the fungicide twice more. Mold growth and mold spores may remain after just one cleaning.

9. Once you have cleaned, planed and sanded everything, spray all wood with a fungicidal protective coating.

After the Cleaning

1. You’ll need to take out and throw away all materials that mold has contaminated. Double bag them in trash bags with a thickness of at least 6 millimeters.

2. After the wood surfaces have dried completely, cover them with a clear plastic coat of sealant. This will protect them from wetness and humidity going forward.

And there you have it! Cleansing your barn of mold is not fun, but it can be done. Follow these steps to remove mold that’s already formed. In the future, thoroughly inspect your barn for leaks and humid conditions to prevent mold from growing in the first place.

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