If your house has moisture issues, winter is the time of the year when you’re going to really notice it. The most common symptoms of moisture issues are mold and mildew. Unattractive and potentially unhealthy as mold and mildew are, they point to a much bigger problem: your home is too wet. Get rid of the excess moisture and your mold problem will vanish.
 
Mold spores are everywhere. Every house has them. The cause of mold is simple. You can easily cure a mild mold growth problem yourself. I’ll tell you how.
 
Mold needs four basic elements to grow: a food source, air to breathe, cooler temperatures and … moisture. Our marine zone winters provide the best conditions for mold to find all four. Remove any of these elements and you reduce the problem. The best element to remove is moisture.
 
Cool temperatures and moisture go together when we talk about mold. When the air is cool, it can’t hold as much moisture (this is when the air feels clammy). Mold likes moisture so mold likes cool temperatures.
 
Mold needs food, too. Outside, molds are helpful in composting and recycling nutrients. But inside, mold likes to munch on varieties of wallpaper glue, greases, paper, fabric, wood and dust. Oh, dust! Dust contains fibers, dead skin cells, and other tiny organic fuzzies that are an excellent food source for mold. 

Here’s a common situation where the four mold-happy elements come together in a perfect storm: You’ve got a house built in the mid-70s. It has electric baseboard or cadet heaters, minimal insulation in the walls, and original bathroom fans.
 
The master bedroom door is kept closed. The heat in the bedroom isn’t on since baseboard heat is pricey and the owners like the bedroom at a cooler temperature. The master bathroom fan isn’t left on long enough to clear moisture out of the room. And there’s plenty of food for mold to feed on in any room. Plus, inadequate (or missing) insulation creates cold spots where damp, warm air will condense (“sweat”).
 
Soon dark spots will appear, usually on the exterior walls where the walls “sweat”, or where moisture likes to gather in a corner of the bathroom ceiling. Or you’ll find mold patches behind the headboard or bookshelf or a puffy chair.
 
The good news is that it’s easy for you to make this situation better.

• First, buy a humidity monitor from the local hardware store. They’re around $10. You want to keep your home’s humidity level under 50%.
• Turn the heat up so it’s at least 67 degrees. Warmer air can handle more moisture.
• Check your bathroom fan to see if it’s actually sucking air out of the room. Turn on the fan, get a strip of 3+ squares of toilet paper and hold it up to the fan. If the paper sticks, the fan is working (whether it’s venting properly is another question).
• Leave the bedroom door open as often and as much as you can.
• Clean up the mold spots with soap and water, treat with sealer, and paint over the area.

 
If this doesn’t fix the problem, try a dehumidifier. If that doesn’t work then it may be time to bring in a professional. But start with these steps first.
 
By the way, the cheapest humidity monitor in the world is your windows. If the inside of your windows are fogging up it means there is more than 55% relative humidity in your home. Turn on your exhaust fans until the fogging goes away.
 
Brent Foster is the owner of Northwest Infrared.“I analyze why a home is behaving badly and then I tell you how to solve the problem.” Foster, the most qualified thermographer in the Northwest, focuses on causes and solutions to home problems like moisture, mold, drafts, leaks, and heat loss. He is available to speak to any community group on improving homes’ energy efficiency. Brent can be contacted at 360-786-6850 or This e-mail address is being protected from spambots. You need JavaScript enabled to view it