Moisture Mayhem

Stop mold before it starts by learning to manage moisture inside your home

Story by Jamey Bradbury

“You have a mold problem” are words any homeowner would dread hearing. At the root of the problem: moisture. Uncontrolled moisture can alter the air quality inside your home, encourage mold growth and cause health problems for your family. According to experts, moisture is the number one contributor to poor air quality inside the home. But you can make your home a safer, more comfortable place by learning to manage moisture.

Modern Houses, More Moisture

Fifty years ago, moisture inside the home wasn’t the problem it is today. Advances in energy efficiency have made our houses tighter and less “breathable,” says Dave Doolen, owner of Rainbow International Restoration. “In the past, there was enough air leakage in the average home that moisture wasn’t a concern. With the way we build today, houses are so tight, you need to plan for proper ventilation to prevent moisture build-up.”

Because where there’s moisture, there can be mold. “Three factors contribute to microbial growth,” says Doolen: “Moisture, warm temperatures and food – basically, any material that goes into a house.” Eliminating mold’s food source is virtually impossible, and turning the heat down in the winter isn’t a very comfortable option. That means managing moisture inside the home is key to preventing mold.

It’s Coming From Inside the House

We all contribute to the moisture level inside our houses just by living. Cooking, showering and even breathing produce moisture that, in a poorly ventilated home, condenses on walls and windows. “You have a cold surface on the outside of an exterior wall and a warm surface on the inside, and somewhere between, you’re creating a moisture layer,” explains Darrell Pilcher, a restoration manager with Taylored Restoration. In tight homes, he says, areas where boxes or furniture sit against a wall prevent proper ventilation, providing a place for mold to grow.

Here are a few tips for managing moisture inside the home:

Install a whole-home ventilation system. “For existing homes, an exhaust ventilation system with fresh air intakes works the best and makes the most sense budget-wise,” says Pete Klebes, owner of Healthy Homes Alaska. For newly constructed homes, Doolen suggests installing a heat recovery ventilator. Both systems produce the fresh air exchanges that are crucial to preventing moisture and mold in tight buildings.

Upgrade your bathroom fan. “People take hot, steamy showers, and their fans aren’t powerful enough,” says Pilcher. “All the moisture that’s created just attacks the drywall.” Many newer, high-quality fans even come with a humidistat that allows the fan to automatically regulate humidity. Wondering whether your fan is powerful enough? Take a listen, says Doolen: “If your bath fan makes a lot of noise, it’s not doing its job efficiently.”

Do regular maintenance. Leaky pipes, water lines under the sink, water supply hoses for the refrigerator and wet appliances: When these break down or go bad, water can soak into the floor or nearby walls. Bryce Huff, project manager for Henry’s Services, Inc., recommends replacing outdated rubber or vinyl hoses that supply water to appliances like washing machines with modern “steel-braided” supply lines. “While you’re having your heating system inspected annually, have someone look at your water heater,” adds Huff. “It only takes a minute more, and it’s one more step to preventing flooding.”

Clean up overflows immediately. “But if it affects multiple layers or levels, that’s when you need to get a professional,” advises Pilcher. Restoration specialists can pull carpets back, set up fans and dry things out within three to five days, before mold begins growing.

Invaders from Outdoors

Moisture from outside can seep into a home, too. “One of the most common points of entry for moisture is ice damming in the winter,” says Huff. Heat loss through attic spaces causes snow to melt on the roof; water runs into the eaves where it cools off and freezes to create a dam of ice. As the water builds up behind the dam, it slowly infiltrates the house.

Proper ventilation can solve ice damming issues, says Klebes, who puts ventilation in the lowest level of a home. “Ventilating from the bottom up is the healthiest for a home; it reduces heat loss and promotes the best air quality. And for people with ice damming, it eliminates that problem.”

Other vulnerable points of entry include windows, doors and garages. “Some garages don’t have the right floor drains, or the floor isn’t sloped,” explains Pilcher, “so the melt-off from your car runs toward the walls instead of the drains, and the drywall just soaks it up like a sponge.”

“We have a lot of bulk snow that sits on the ground and thaws, supersaturating the ground outside your house,” adds Pilcher. “If there’s poor drainage in the soil, that excess water can make its way into your crawlspace and contribute to overall moisture levels.”

Keeping snow cleared away from the sides of your house, inspecting your crawlspace and replacing old caulking around windows can help keep water from getting indoors. “You can’t rely on waterproofing techniques, though,” warns Huff. “You also have to direct water away from your house through grading, proper drainage and guttering.”

Signs and Solutions

Not sure whether you have a moisture problem? Moisture build-up on windows, discoloration in sheetrock, black spots on the ceilings or walls and increased indoor humidity are all indicators that your home isn’t dry enough. A musty or damp smell usually accompanies early mold growth.

If you’re still unsure, you can have an industrial hygienist sample the air to check for mold spore levels. Specialists can use moisture meters to check your walls and carpets, down to the subfloors, to identify moisture problems. Many restoration companies will even offer a free assessment of your home.

Even if your home doesn’t have mold or excess moisture, you may still want to consider making some upgrades for better air quality, says Klebes. “Without a ventilation system, the indoor air quality is at least five to ten times worse than the air right outside the front door. Poor air inside the home is why many homeowners experience allergies, colds and sickness.”

While not all molds are necessarily harmful, some can cause significant respiratory problems, particularly for the elderly, infants and people who are sensitive to mold spores. Certain mold spores are highly toxic and can cause serious health problems. “Ultimately, all mold should be considered potentially hazardous, because you never know how you’re going to react,” says Huff. “If you identify a problem, get it taken care of early.”

For substantial mold growth, it’s best to leave clean-up to the professionals. While some surface molds can be cleaned with a diluted bleach solution, though Klebes emphasizes that proper ventilation is the key to permanently solving the issue. Adds Doolen: “You have to think about modifying your behavior or changing the airflow in your house so the problem doesn’t just reoccur.”

Resources: Dave Doolen, Rainbow International Restoration; Darrell Pilcher,; Pete Klebes,; Bryce Huff,