News

Jul 19, 2023

How to inspect your home for mold, room by room

Mold spores float through the air and settle on surfaces, even in the cleanest homes. They get tracked inside on our shoes, pets and bodies, as well as through gusts of air. Once spores meet moisture

Mold spores float through the air and settle on surfaces, even in the cleanest homes. They get tracked inside on our shoes, pets and bodies, as well as through gusts of air. Once spores meet moisture and find a food source — whether it’s dirt, dust, wallpaper glue or the paper on drywall — they can grow in as few as 24 hours, causing health issues and damaging structures.

Nancy Bernard, a public health adviser and program manager for Washington State Department of Health’s Indoor Air Quality program, says mold’s job is to decompose whatever it’s growing on. That’s fine, she says, as long as it’s “decomposing outdoors where it belongs.”

Indoor mold growth typically indicates a water problem. All it takes is one persistent drip over time for mold to take root and destroy a large part of a home, says Brian Fish, a Navy veteran who operates North Sound Mold Solutions in Mount Vernon, Wash.

The best ways to prevent mold growth in your home include keeping humidity levels in check (the Environmental Protection Agency recommends a level of 30 to 50 percent) and dusting regularly with a damp cloth. Performing regular visual inspections of each room can also help you spot and squash issues before they require costly professional remediation. Here’s how to check each room in your home for mold and what to do if you spot signs of moisture.

Growth happens when mold spores land on wet surfaces, so it’s important to check window frames frequently for condensation. “The mold isn’t growing on the vinyl, it’s growing on the dirt and oils” that settle on it, says Bernard. If you can’t reduce condensation, wipe the window daily with a dry cloth.

Thick window treatments, especially if they’re little-used, can be another prime hiding spot for mold and moisture. Fish recommends hanging them an inch or two above the top of the window to better allow air to circulate.

Mold also likes to hide behind furniture. Bernard says to put big, bulky pieces on interior walls, which tend to have less condensation than exterior ones. If that’s not possible, leave at least a few inches between the furniture and the walls to allow air to circulate. Or, Fish says, regularly pull furniture away from the wall and look behind it.

If you find mold on your mattress or furniture, you can try to clean and dry it, but if it still has a musty smell when you’re done, Bernard says the mold is still there. Putting it outside in the hot sun might help.

For porous materials such as carpet, take a preventive approach. Clean up pet accidents and spills quickly and completely, and vacuum frequently with a HEPA filter.

Most closets are closed off, unheated and full of clutter — creating the perfect conditions for mold. Cracking and/or opening doors occasionally will help increase airflow, or you could replace the closet doors with curtains, as Bernard did in her home. Scan closet walls and corners from top to bottom, and remove ground-level items to inspect the floor. In closets, attics and any other area used for storage, Fish suggests replacing cardboard boxes (a favorite of mold) with plastic storage bins that seal.

Check for leaks around the standpipe — the thruway where water discharges from the washing machine — and make sure the drain hose hasn’t come loose. Drain hoses wear out and leak so be sure to replace them every five to 10 years. The same goes for washer door seals; if they’ve become brittle or are covered in mold or mildew that won’t wipe off, it’s best to replace them. Depending on the model, this can usually be done without hiring an appliance repair professional.

Dryers should vent to the home’s exterior, not up into the attic. Fish recently inspected a home where “there was probably 15 years of wet dryer lint blown into the attic and it rotted the sheeting and damaged the framing.” Also check the dryer vent duct for cracks and kinks so wet lint isn’t blowing (and growing mold) on the wall behind the unit.

Homes are built more airtight than they were in the past, and some type of ventilation in the laundry room is important to reduce humidity, Fish says. If your laundry room has a fan, run it frequently and ensure that it vents to the exterior of the home.

Fish says to slide out your appliances, particularly the refrigerator, periodically to inspect and clean around and under them. If your fridge has a built-in ice-maker or water dispenser, make sure the water line is kink-free to prevent leaks that can lead to mold. Check every appliance that has a drip pan regularly, including water heaters, furnaces and HVAC systems, even if they are hard to access.

Look under the sink (yes, all the way in the back) often. Fish recommends using rubber mats in the cabinet under the sink to catch potential drips. “Most folks don’t have custom wood cabinets so it’s all particle board or MDF-type cabinetry,” he says. “Once that stuff absorbs water, it just puffs up,” molds and spreads to the wall. Monitor all caulking, especially around the backsplash, for cracks or shrinkage that can allow water to seep through.

Do a tissue test to ensure that fans, including the one in your range hood, are working properly: Does a piece of facial or toilet tissue stick to the cover when it’s running? If yes, then you’re good. Running fans throughout the home can help maintain recommended humidity levels.

Fish says to remove fan covers to clean them fully. “It’s the most common place we never see people clean,” he says. Check inside the fan for mold, too.

Of course bathrooms are prime spots for mold, but the potential breeding grounds go beyond walls and under-sink cabinets. People often store slow-drying items such as paper products and towels in bathroom cupboards. Inspect them for signs of moisture. Also look at all bathroom caulking and wipe surface mold off, but note that if the caulk is impregnated with spores, it needs to be replaced. Never caulk over caulk; it won’t adhere properly and you’ll just be giving the mold more food.

Sit backward on your toilet for what Fish calls “the straddle test.” If it wiggles from side to side, the floor seal could be leaking. Check behind the pedestal on the floor as well, where condensation from the tank often drips unseen.

Bubbling paint, peeling wallpaper and swollen floorboards could indicate a problem below the surface. If you find mold, the EPA says you can usually clean a 10-square-foot area independently. For anything larger, call an expert.

Jerica Pender is a freelance writer in Olympia, Wash.