Energy Adviser: Close the door on menace of mold



You may get knocks on your door tonight from superheroes, ninjas, princesses and pumpkins, but there's one visitor in your home that's no treat at all and requires a trick or two to stop in its tracks: Mold.

Sooner or later, mold will darken some damp corner of your home. Catching it early and improving ventilation will help control it as we head into the winter months.

"There's no avoiding mold in the Northwest, because its spores are in the air we breathe," said Bob West, energy counselor at Clark Public Utilities. "And unfortunately, mold presents a hazard not only to our homes, but to our bodies as well."

Mold and mildew, a kind of mold, eat anything organic and regenerate using spores. That's why those black spots on the caulk around your bathtub or between your kitchen tiles will grow and spread if left alone.

Mold spores fly into your home from outside. They attach themselves to clothes and pets. Spores sweep in through any opening to the outside — doors, windows and vents. Once inside, they float about like dust particles and fall onto moist places.

A few hundred to tens of thousands of spores per cubic yard can invade your home. Once they settle on a moist spot, they reproduce, or "colonize," rapidly. The colony sprouts millions of spores that float back into the air and eventually settle on every surface of your home.

"We build our houses out of the very stuff molds like to eat: cellulose," West said. "Moisture lurks in our kitchens, bathrooms, crawl spaces, doors, windows, under carpets and behind ceiling tiles. Controlling mold means controlling that moisture."

Improving ventilation

Improving ventilation is the best way to control moisture and mold, especially in the kitchen and bathroom, because these rooms should have ventilation fans. West encourages homeowners to use the "toilet paper test" to check the strength of these vents.

"Take one square of TP and hold it near the vent," he said. "If it sticks to the vent then everything's working. If it fails to, you have a problem. Each fan should push moist air outside at 100 cubic-feet-per-minute."

Bath and kitchen exhaust fans can help keep your home's relative humidity levels below 50 percent, which is a healthy level according to the U.S. Environmental Protection Agency Energy Star program. "A level of 40 percent is better, but may require adding a dehumidifier to your home," West said.

Molds also pose health hazards. Exposure can cause stuffy noses, sore throats, eye and skin irritation, and wheezing. Anyone with a serious allergy to mold may suffer more severe reactions.

If an area of mold in your home is large — covering more than 10 square feet — seek professional help. Otherwise, you can clean the mold up yourself using common solutions such as bleach, Borax, vinegar, ammonia, hydrogen peroxide or baking soda. Wear ventilated goggles and long rubber gloves that cover up your arms. The EPA also suggests an N-95 respirator so you don't inhale mold. If you have mold in rugs, ceiling tiles or anything porous, you may have to throw them away, because you won't be able to clean them completely.

The EPA website — — provides a helpful booklet on mold and mold cleanup.

To prevent further mold growth and keep the problem at bay, fix any leaky plumbing and make sure moist areas are well-ventilated. Never paint or caulk over moldy surfaces.

"Mold occurs naturally, but by keeping excess moisture out of the home and diligently cleaning up mold when it appears, homeowners can reduce the chances of mold damaging their home or their health," West said.Energy adviser is written by Clark Public Utilities. Send questions to or to Energy Adviser, c/o Clark Public Utilities, P.O. Box 8900, Vancouver, WA 98668.