Mold Prevention
by Homeowners & Tenants

Household activities produce large amounts of indoor moisture vapor, including cooking, bathing, breathing, perspiring, evaporation, cleaning, and ironing. Homeowners & tenants control moisture by using ventilation strategies, using furnaces & air conditioners, and wiping up water.

FAQ: I have what looks to be mold around my windows, in my bathroom, behind furniture, and mildew in my closet.  Everything seems to be okay part of the year, but then it all comes back.  What ‘s going on?  What can I do?

Answer: This problem is usually found in older houses.  They tend to have single-pane windows and depend on windows for ventilation.  These house are also air leaky through walls, floors, and ceilings.  Worse conditions are present when the house is over a crawlspace and central heat is not used.

Sometimes these conditions are aggravated by water draining into the crawlspace, a vapor barrier over the crawlspace floor is missing, or dryer vents terminating in the crawlspace.  There are other conditions too.

1. Open windows while bathing.  Better yet, install bath area fans on timers or humidistats.  The fan should run 10 minutes after bathing.  This eliminate 1 cup of water per shower from the air

2. Take short showers. A five-minute shower puts 1 cup of moisture in the air, which settles on everything in the bathroom

3. Dry the bathtub/shower with a towel when finished.  The goal here is avoid evaporation to dry them.  Let the towel dry outside.

4. Open windows while cooking.  Better yet, install a range hood or kitchen area exhaust fan.  Open a window, door, or run a fan whenever water is heated.

5. Use a dehumidifier, set between 35-45%.  It will heat the house while lowering both absolute and relative humidity. At a minimum, get one with an ENERGY STAR rating as they use a lot of electricity.  However, it can replace a heater you’re already using.

6. Prop closet doors open.  Stagnant air and mold/mildew go together.  Air flow in the room should help.  Air flow should get between clothes, so don’t jamb them in there.

7. Make “storm windows”.  Moisture condenses easier on single-pane windows than it does on dual-pane windows because the “cold” outside window is separated from the “warm” inside one.  Be sure it’s air tight.  Kits are available in a building supplies store.  They’re plastic sheets.

8. Correct the dumb stuff.  If the dryer is ducted into the house or crawlspace, make it go outside.  If water is draining against or into the foundation, stop it!  If the crawlspace seems dry, add a   vapor barrier over the ground.  If there are any plumbing leaks, fix them!

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