Mold & Mold Prevention

QUESTION: An addition over a crawl space, a large family room, has been odor-free for 40 years, but now it has a moldy smell. I don't quite understand why it is occurring after 40 years, especially during the summer drought. I had a company assess the situation, and it suggested putting a pool-liner type covering on the earth floor of the addition, sealing the crawl space completely and installing a dehumidifier at a considerable cost. The company insisted that closing the crawl space would work. What do you think?

ANSWER: It's all a matter of reducing humidity in the crawl space and in the family room to end that moldy smell. Many new house are virtually airtight, which helps keep them dry, but can result in stale air and numerous other pollutants. In my experience, venting a crawl space in the warm season is still the way to go. A proper sealing can be quite expensive. A barrier on the earthen floor is a good idea, but I say install as many vents as practicable; you really must allow all that water vapor to escape. Also, a dehumidifier is expensive to operate, while ventilation is free. Make sure the crawl space ceiling is insulated with fiberglass, with a paper backing, to prevent water vapor from coming up into the family room. But why it occurred after 40 years beats the heck out of me.

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QUESTION
I had my house power washed a month ago, and now a lot of the white paint is moldy.  The power washer said it was my paint that caused it.  My neighbors’ houses, which are not white, are not moldy.  How come?  How can I keep the mold off my house?

ANSWER
For starters, the power washer is wrong to say your paint is to blame.  Most exterior paints have a mildewcide in them that helps keep the mold away for two years.  But the power washer may not be too far off.  Actually, he helped cause the mold by making the paint very wet.  And the white color allowed the water to stay on the surface longer because it slowed the evaporation process.  Darker colors absorb heat and dry faster, reducing the chance for mold to grow.   Remove and kill the mold with a solution of one part bleach and three to five parts water.

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Question
I have been reading about how much mold contamination can destroy your home and also can be a serious health risk. Is there anything I can do to prevent this?

Answer
The key to mold control and leaks is moisture control. Solve moisture problems before they become mold problems!

* Fix leaky plumbing and leaks in the home as soon as possible.
* Watch for condensation and wet spots. Fix the source(s) of the moisture problem(s) as soon as possible.
* Prevent moisture due to condensation by increasing surface temperature or reducing the moisture level in the air (humidity). To increase surface temperature, insulate or increase air circulation. To reduce the moisture level in air, repair leaks, increase ventilation (if outside air is cold and dry), or dehumidify (if outdoor air is warm and humid).
* Keep heating, ventilation, and air conditioning (HVAC) drip pans clean, flowing properly and unobstructed.
* Vent moisture-generating appliances, such as dryers, to the outside where possible.
* Maintain low indoor humidity, below 60% relative humidity (rh), ideally 30-50%, if possible.
* Perform regular building HVAC inspections and maintenance as scheduled.
* Clean and dry wet or damp spots within 48 hours.
* Don't let foundations stay wet. Provide drainage and slope the ground away from the foundation.

These tips are some basic guidelines to help you to understand and prevent mold from growing and living in your home. Mold can gradually destroy the things they grow on. Prevent damage to your home or structure, which will help you save money, and avoid potential health risk by controlling moisture and eliminating mold growth.

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Question
I had mold in one of my rooms, small black spots on the wall. I wiped them with a bleach solution (two parts bleach and one part water), and nothing happened. What is wrong?

Answer
The bleach solution should have killed as well as removed the mold. But make the solution one part bleach and three parts water, and make sure the bleach is household chlorine. And instead of using a cloth, paint it on with a paintbrush. Wear skin and eye protection.

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