How Mold and Mildew are Related to Attic Insulation

As homeowners (or potential homeowners), we hear all the time about the dangers of mold in bathrooms, kitchens, and basements. Did you know that mold and mildew in the attic may also be a concern? 

Homeowners and home buyers should include the attic area in their mold inspections. If you find mold in your attic, the cause and cure may be simpler and less expensive than you think.

Contact SoDak Insulation for a free, comprehensive attic inspection when you’re ready to buy or sell your home. Our professional team is diligent, timely, and transparent with all our clients.

We’ll detail all your attic mold remediation options and find the plan best suited to your budget, closing deadlines, and health.

mold and mildew in attic

How mold grows in an attic

The whole point of insulation in the attic is to help heat stay in your house, so that it doesn’t reach the roof. If your attic insulation works properly, it prevents the radiant heat from your home from escaping through the roof. 

With a properly installed vapor barrier and thick, deep insulation, any moisture from the house stops in its tracks before it hits the attic. Moisture is the breeding ground for mold, so ensuring a dry attic space is paramount to mold prevention.

Mold in the attic typically forms on top of the insulation surface, not below it or embedded in mounds of sprayed fibers. Here’s how that happens. (Hint: it’s not what you may assume.)

When moist air from your attic meets cool or cold roof sheathing, condensation occurs. Mold grows in moist areas, but cannot gain a foothold without a food source. Since most attic insulation does not “feed” mold, any spores that grow likely come from the roof sheathing instead. 

If you see mold spores on the surface of your insulation, they probably dropped in from the roof sheathing. Of course, an inspection will tell you if your attic mold is more systemic than on the insulation surface.

Treating mold in your attic

Once you determine the source of the mold spores in your attic, remediation can be relatively simple. If you discover mold spores on the roof sheathing, that’s where you’ll focus your cleaning efforts.

Applying a mildewcide to any mold-covered areas on the roof kills the spores and can prevent new ones from forming. You can usually apply the same chemical to the insulation surface to kill any active spores.

Here’s some good news. Mold and mildew in the attic typically don’t pose a threat to your health. Why? Because the “stacking effect” of your attic insulation prevents surface mold from migrating into the rest of your home.

So, once you’ve treated the mold source, you may not need to replace any insulation. If you have extensive mold in your roof, and consequently, a thicker coating of mold on your insulation, you may decide to replace it.

A full insulation clean-out is certainly an option, but you could potentially choose to replace the top couple of inches of fibers only.

Remember, it’s crucial to keep the materials surrounding your insulation mold-free to ensure a pristine insulation surface. 

Reducing moisture in the attic

If you discover mold on your roof sheathing, you can take several measures to dry out your attic and reduce the potential for mold and mildew.

    1. Clear all attic vents. Improper installation and settling may cause attic insulation to block the vents in your attic. Proper air flow is paramount to maintaining a dry, mold-free environment. Ensuring your attic vents remain unblocked with regular checks can help you avoid the moisture that grows mildew.
    2. Ensure proper levels of insulation: Having a “just right” amount of attic insulation is an essential piece of your ambient attic humidity and temperature. Too much or too little can create conditions ripe for condensation to occur.
  • Seal all bathroom and kitchen vents into the attic. Since bathroom and kitchen air is notoriously moist, you must make sure to seal it off from attic air. In fact, new building standards recommend restricting the use of bathroom and kitchen vents through the attic. To ensure that warm moist “home” air does not mix with cooler attic air and condensate, fewer holes between the two environments make sense.
  • Inspect and maintain your roof. Since your roof is your first line of moisture defense, a leaky one isn’t doing its job. Visually inspect your roof each season for items like curling shingles, rotted fascia boards, large and small debris, and visible holes. Pay close attention to the seams around chimneys and skylights, as those are prime spots for leaks to develop. Of course, you’ll also want to check for water damage on the walls and ceilings of your home. It’s a good idea to have a professional help you inspect your roof completely and safely. You should check your roof each year, and after severe storms. You’ll also want to keep an eye out for ice dams during the winter months.
  1. Install a dehumidifier. Once you’ve addressed all of the structural prevention measures for mold and mildew in the attic, you can keep your space dry as the seasons dictate. During an especially wet spring or summer, a dehumidifier can help ensure that conditions don’t deteriorate in your attic.

mold and mildew in attic

Help! I have mold and mildew in my attic. What now?

Remember that most mold problems in the attic remain on the insulation surface and don’t pose a threat to your health. However, it IS essential to address the mold and mildew causes with the help of a professional.

If you’re concerned about mold and mildew in the attic, contact the professional team at SoDak insulation. We will perform a free attic inspection, and offer our best guidance for how to proceed. 

We’ll recommend only the remediation you need. (i.e., if you don’t need to replace all of your insulation, we’ll tell you as much.) Plus, we can help you pinpoint the root cause of moisture in the attic so you can address it quickly and safely.

Though mold on your insulation may not pose an immediate health threat, it’s crucial to address it swiftly. Not only can you preserve the quality of your insulation, but you may also save significant money on massive repairs in the future. 

Visit the SoDak website today to set up your free, no-obligation home visit. Our team embraces safer service delivery guidelines in our socially-distanced “new normal.” We’re excited to help you keep your home a sanctuary of lasting peace of mind and comfort.

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