Skip to content
(401) 635-0040

What causes Mold growth?


what causes mold growth

Mold spores are naturally occurring and can be found everywhere, including on the interior of every home, school and office building. Excessive moisture combining with mold spores is what causes mold growth. So, any leak, water seepage or even condensation issues in a building have the potential to become a mold problem. Basements, bathrooms, kitchens, laundry rooms, and attics are the most common areas in the home with the potential for mold growth since these areas naturally have more water leak or seepage concerns. Carpeting in areas with moisture or water issues, such as in finished basements, increases the possibility of mold growth and mold under or in the carpet is usually not visible. Many modern building materials and practices, such as sheetrock or drywall for construction of finished walls and ceilings, contribute to a growing problem with mold related health issues in homes. Older wall material, such as plaster, is not nearly as susceptible to allowing mold growth as paper wrapped sheetrock and drywall. Many processed wood products such as oriented strand board (OSB), used as wall and roof sheathing, and hardboard used in many building and furniture products, are also much more susceptible to mold growth than simple wood products.


The relatively recent practice of making houses “tight” for energy efficiency reasons can also result in more mold problems. Houses built to high efficiency standards have less air flow or ventilation. The lack of ventilation tends to exacerbate mold problems by limiting the exchange of fresh air throughout the building. Ventilation is also important for helping homes “dry out” if there are moisture issues. Therefore, if mold starts growing in a tight house the problem becomes much more noticeable and unhealthy to the occupants than in an older “drafty” house.

Mold has also been known to grow in surprising areas of the home. Central air conditioning systems and their associated duct work provide a damp, dark space where mold tends to thrive. What could be worse than having mold spread throughout your house every time your central air conditioning system turns on? Almost every refrigerator has a drip pan underneath which catches condensation and the pan is designed to eventually allow evaporation of this moisture. If the pan fills with dust then mold growth will soon follow. Window sashes and seals are also prime areas for mold growth since condensation accumulating on the glass will drip down into corners and crevices where dust and dirt collect, resulting in mold growth. The fact that most bedrooms have at least one or two windows increases the concern with mold growth here.


Rhode Island's proximity to the ocean, and our heavy rain and snow seasons, provide an ideal environment for mold growth. It is common to find mold in basements and attics in Rhode Island and Massachusetts homes due to this humid and damp environment. Flooding or leaks inside or behind walls increase the possibility of mold growth. Since inspectors cannot see behind walls or above ceilings, Air Sampling is used to determine if there is a high mold spore count in the house.

Molds break down dead organic matter such as fallen leaves and dead trees. Indoor mold growth should be avoided for health reasons. Molds reproduce by means of tiny spores. The spores are invisible to the naked eye and float in the air. Mold may begin growing indoors when mold spores land on surfaces that are wet. There are many types of mold, and none of them will grow without water or moisture. The mold spores can also sit dormant for many years before becoming active due to moisture or water issues in a home or building.

Mold Inspection vs. Mold Testing

What's the Difference?


Mold Inspection vs. Mold Testing