Excessive moisture in home can lead to mold
Q. I have made improvements to my brick house over the years. It seems as though mold and mildew problems have gradually gotten worse. What can I do to correct this problem of worsening mold?
A. Excessive mold in a home can be more of a health problem than most people realize. Everyone knows mold and mildew looks bad and may create a foul odor. Many types of molds cause allergic reactions in people and some are actually toxic. The only way to know exactly what type of mold infestation you have is to have mold samples tested.
When people make improvements to their homes, particularly energy-saving ones, the house becomes more airtight. This does two things to exacerbate mold problems. First, less fresh outdoor air leaks into the house. Second, moisture from indoor sources builds up indoors to the point where mold thrives.
One method to reduce allergic and other health problems related to mold is to install some good-quality room air cleaners. Most allergies are actually to the mold spores (seeds). These are relatively large particles, so most air cleaners will catch them.
Being large particles, they often settle back down on surfaces and furniture before making it into the furnace return air ducts. For this reason, room air cleaners which are close to the mold spores, are often more effective than a central air cleaners.
For mold to thrive in a home, it requires a food source and persistent moisture. Almost any organic material, dust, fabrics, dead skin cells, etc., can be the food sources, so it is difficult to eliminate the food source. It is much easier and more effective to try to eliminate the persistent moisture.
The relative humidity inside a home is a measure of how much moisture is in a home. By keeping the relative humidity below 50 percent, the release of mold spores is greatly reduced. During cold weather, when windows, doors, walls, and plumbing fixtures are colder than the room air, the relative humidity near them can still be much higher than 50 percent. At 100 percent relative humidity, water vapor condenses into droplets and dampness.
First, clean up any areas, such as the basement, bathrooms and laundry rooms, where there currently are minor mold and mildew problems. Wear gloves and a breathing mask because you are not sure what type of mold you are dealing with. Use a solution of one quart of chlorine bleach to one gallon of water. If there are large areas of dark mold on walls, have it tested before trying to remove it yourself.
Once you have the indoor humidity level somewhat under control by using vent fans in bathrooms, drying off the shower walls, emptying any standing water in sinks, glasses, etc., turn your attention to the exterior of the house.
Depending upon the condition of your roof, windows and doors, much moisture can be entering your house from outdoor, particularly during the summer. Check for possible leaks. You might consider using a sealer on the exterior of your house.
Don't expect improvements immediately. It can take quite a while for the damp areas to dry out enough to no longer support mold growth. Also, mold spores can stay dormant for a long time and can sprout again as soon as an area gets damp again.
• Ms. Builder's column appears Sundays in Homes Plus. Send questions to Ms. Builder, 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit dulley.com/msbuilder.
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