Mold growth occurs when conditions are favorable. These conditions include:
- Moisture This can come in the form of humid air, dripping pipes, or water intrusion due to flooding. Mold will grow when the relative humidity is roughly 50 percent or higher.
- Food Mold will feed on wood, paper, cotton, and leather. Drywall with its paper coating offers ideal food for mold spores. Mold can grow in dirt or dust if the conditions are right.
- Right Temperature Spores will proliferate in temperatures ranging from above freezing to below 120 degrees. Summer-like temperatures (70-90 degrees) are especially conducive to mold growth.
- Time Mold growth can occur in 24 hours or it may take as long as 10 days, depending on the conditions.
- Stagnant Air Insufficient ventilation contributes to moisture buildup.
Mold is an opportunistic pathogen, which means it will take advantage of any conditions favoring its growth. According to Michael Pugliese, author of The Homeowner’s Guide to Mold:
Its spores can travel to neighboring rooms, land there, and not grow at all. They can sit there dormant for months or even years. Then one day the right combination of temperature and humidity will activate them, allowing them to germinate and start growing. That’s why, during the remediation process, proper containment is a must to prevent cross-contamination.
In the photos above and below, you’ll see what can happen when the conditions are favorable for mold growth. This home was unoccupied and on the market for sale. The furnace was inadvertently shut off during freezing weather, and when the temperatures rose, pipes burst and water leaks occurred. The lack of ventilation only added to the problem.
Mold commonly appears as black or brown. However, as seen above, it can appear in a variety of colors. According to Pugliese:
No mold growing in a home is good mold—period. Whether the mold is white, black, green, maroon, turquoise, gold, or brown, it is still mold, and at some point it may produce spores or gases known to create adverse health conditions to human beings and pets.
It is imperative that we remain vigilant when it comes to our indoor environments. Understanding what causes mold to grow can go a long way toward keeping us safe and healthy at home, work, or school.
Wondering if hidden water damage is impacting your health? See A Beginner’s Guide to Toxic Mold.
Ruth Ruddock says
I jut found your new web site again…and it is great!
Have a question for you on mold. We are living in a concrete block house that has had mold in the bedrooms…on the block! We had a cleaning and remediation company come in, while we left for three days, and they cleaned it completely, using Nature’s Eradicator (elfbrands.com) and we were pleased with results when we returned to the house. Now that the weather is warming up again (here is Western Nebraska) I noted that the mold is returning to the corners where it had been before, and the telltale smell is starting to creep in slightly. I sprayed the area with the mold cleaner (which is not registered with EPA, but owner of company assured us it does kill mold on contact) and it is subsiding again. The humidity in the house is 30 to 40 % now, so that may not be a factor. In checking with my hardware store about anti-fungal paints, she said that we must first make sure the mold is killed before putting the paint on the concrete blocks….there are many tiny holes in the block surface, so we will try putting portland concrete on it to fill in the holes…it was thought that the holes are keeping mold spores and promoting the growth again. At this point we are hoping to make this work, while still living in the house.
We can not afford to vacate the house anymore than we already did when the remediation people came through. It was just a massive clean up with some paneling removed, blocks cleaned up, all surfaces were cleaned in the house. Any thoughts from you will be appreciated. Please answer on my private email address if you will.
(Yes, I am the same Ruth that wrote from Wisconsin a few years ago…moved out here in April, last year, to live with friend.)