Every week, home inspector Lars Knobloch gets at least one phone call from someone with a potential mold problem in their home.

Sometimes they can see what they think is mold and want to be sure. Other times, they just don't feel well and want to rule out mold as the culprit.

"It is real," said Knobloch, who owns Nordic Home Inspection in Fargo and does real estate inspections as well as testing for mold, asbestos, lead, radon and allergens. "It's a serious matter."

Casey Bartz of Moorhead recently dealt with mold in a home he was purchasing and said while there are a lot of home remedies for mold removal online, he would rather deal with professionals.

"There's a lot on the internet that can be out there to scare you," he said. "Having an actual person I could speak to about it helped me out a lot."

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Knobloch was inspecting the home when he discovered mold along the baseboards. The air in the home also did not smell fresh, Bartz said.

So Knobloch did an air quality test, not only in the basement where he saw mold, but also on the home's main level. The results revealed toxic black mold.

Bartz was then able to factor in the cost of mold removal when he negotiated the house's price.

As he worked in the home before the mold was removed, Bartz noticed that he didn't feel well. But once the basement carpet and moldy sheetrock were removed, his home smelled a lot cleaner and he felt a lot better.

Having experienced the effects of mold, he knows what to watch out for and he knows how important it is to take care of problems that could lead to mold before that happens, he said.

Reasons for mold

Too much moisture can create an ideal environment for mold.

Indoor air quality expert, Ken Hellevang, a North Dakota State University professor and NDSU Extension engineer, said mold will grow on wet materials in 24 to 48 hours.

"In our climate, we find a lot of potential for moisture problems in homes," he said.

In the summer, homeowners may deal with damp basements as the ground water level rises. In the winter, condensation increases the moisture level in homes, he said.

Knobloch usually finds mold where water might drain such as around a utility room, water heater, sinks, washing machines, and bathtubs, he said.

Common causes are if the soil around your home slopes toward it or if the downspouts are not angled away from your home. In those cases, rainwater drains toward the foundation, creating a moist environment where mold will thrive. Mold might then grow on the back of sheetrock or behind baseboards.

"Mold really grows well in dark areas," he said.

Mold can be caused by the following: flooding, sump pump failure, condensation on windows, soap scum in showers, firewood stored indoors, humidifier use, venting clothes dryer exhaust indoors, line drying clothes indoors, and a leaky or poorly ventilated attic.

"No one goes up in the attic," Knobloch said. "I usually recommend people go up there once a year to check for minor roof leaks."

Closets, especially those on exterior walls, can also be conducive to mold.

In "Keep Your Home Healthy," Hellevang's guide to improving indoor air quality, he explains that closets are higher in humidity than the rest of the house in the winter because the temperature inside the closet is often cooler than the rest of the house.

Mold is found more frequently in newer homes because older homes are draftier, don't often have finished basements, and often have plaster walls, Knobloch said.

"Almost every time I see an issue, it's with sheetrock," he said.

Health risks

Mold usually has a musty smell, but people might not realize they have a mold problem if it's growing where they can't see it.

Sometimes illness alerts them to a problem.

"Many people contact me because they're sick," Knobloch said. "They have one of these health symptoms and they wonder if they have mold."

People's bodies respond differently to mold exposure. Some might have a severe reaction while others could experience no symptoms at all.

Health risks are greater in infants and children, the elderly, people with respiratory conditions or sensitivities, and those with severely weakened immune systems, according to the Minnesota Department of Health.

Hellevang said research is finding people are more sensitive to mold growth than they used to be.

According to Mayo Clinic, mold allergies cause the same signs and symptoms as other upper respiratory allergies. Symptoms can include: sneezing, runny or stuffy nose, cough and postnasal drip, itchy eyes, nose and throat, and watery eyes.

With a mold allergy, symptoms generally worsen with each exposure.

Asthma symptoms can be triggered by exposure to mold spores and in some people exposure to certain molds can cause a severe asthma attack.

Mold can also cause infections, with problems ranging from flu-like symptoms to skin infections or pneumonia.

Irritant reactions are similar to allergy reactions and may also include headaches.

The symptoms of a toxic reaction might include flu-like symptoms, eye and skin irritation, trouble breathing, headaches, nervousness, dizziness, difficulty concentrating and extreme fatigue.

Knobloch offers mold testing from $50 to $75 for a quick inspection where he does not discover any mold, to $250 to $350 for more in-depth air quality testing.

What to do about it

Mold can be an issue, even if it's in a part of the home where people don't often go because mold spores travel through the air and can live for a long time under many different conditions, Knobloch said.

A bad case of mold could cost around $10,000 to be removed by a professional, he said.

Smaller growths can be cleaned.

Mold can be removed from hard surfaces like hard plastic, glass, metal and counter tops by scrubbing with a soap or detergent, Hellevang said in his indoor air quality guide.

The Minnesota Department of Health suggests cleaning moldy surfaces with a mixture of bleach and water. Knobloch recommends a stronger solution.

"You clean off the surface mold and then the bleach evaporates and you're just feeding the mold with more moisture," he said.

Knobloch said mold is like a tree that has roots growing into the surface it's sitting on.

It is impossible to completely remove mold from porous surfaces like paper, insulation, sheetrock and carpet padding, so those materials should be thrown out, Hellevang said. Mold growth on wood may need to be removed by sanding, he said.

Mold particles in the air can increase when mold is disturbed, so you should wear protective equipment when working around mold, the Minnesota Department of Health stated.


The key to avoiding mold and its accompanying health problems is by controlling humidity in the home, Hellevang said.

He suggests buying a relative humidity gauge and keeping humidity between 40 and 60 percent in warmer months. To reduce condensation potential in the winter, keep the humidity level at 30 to 35 percent, he said.

Anything below 30 percent can lead to dry skin and nasal passages, increasing the potential for respiratory illnesses. It can also cause wood shrinkage and increase the incidence of static electricity shocks, he said.

The Minnesota Department of Health recommends drying all wet materials as soon as possible. For severe moisture problems, use fans and dehumidifiers and move wet items away from walls and off floors.

If you've cleaned up a mold problem and it grows back, that may mean you have to throw out the material it's growing on or moisture in the area is not controlled, the Minnesota Department of Health said.

Forum reporter Sherri Richards contributed to this story.