Why Mold Grows in the Attic
Updated: Feb 22, 2019

It is a well-known fact that mold grows wherever there is humidity, so when you hear about mold in the basement, bathroom, or other low-lying areas, it comes as no surprise. And while the attic does not generally have plumbing or, it is a major source for moisture, leaks, and condensation.
Attic mold is most frequently due to roof leaks, which often remain unnoticed, especially if they are small. Roof repair is delayed; temporary fixes are made and then forgotten, and any other number of reasons. Again, mold likes moisture and when there is a warm climate added to the equation, it cultivates without issue and thrives among food sources that include structural wood, stored boxes, and insulation. Because attics are not seen as often as other parts of the house, it can breed mold without being realized for a long period of time.
Locating the Source of Moisture in the Attic
Roof problems are difficult to locate, so hiring a professional who is trained to locate even the smallest issues will prevent problems from worsening over time. In general, attic moisture is caused by leaks, improper ventilation of pipes or vents that are not correctly installed.
If you see mold, a mold assessor will perform a visual inspection of the area in an effort to find the underlying source. Regardless of the age of the home, moisture can and does occur in practically any part of a house.
There are also telltale signs you can check for on your own, that are present when there is moisture or mold in the attic.
Leaking Roof
A leaking roof is often discovered because of signs in the attic. If these signs go undetected or unrepaired, moisture will continue to build up and increase the chances for mold growth.
Vapor barriers tend to collect condensation and if not dried out, will cause mold problems.
Check areas around plumbing stacks, attic windows, chimneys, venting, and skylights. These places are ideal for possible leaks and moisture accumulation.
Water vapor and leaks cause discoloration on roof rafters or insulation.
Roof valleys where different roof angles meet often attract moisture.
Vents and Exhaust Fans
Homes have several fans and vents installed to improve air quality. However, if these are not properly installed or routed outside of the home, they are primary sources for condensation buildup. Air moves upward and when vents and fans are capped in the attic, warm moist air gets trapped in the attic after long hot showers, cooking, and operating the clothes dryer. If you have dryer vents, bathroom exhaust fans, or vents in the kitchen that are routed to the attic versus outside, it is worth the investment to have them redirected outside of the house, or at the very least have a vapor barrier properly installed.
Contact Us Today
Mold growth can be reduced and prevented. Even when you detect mold, it can be remedied through a mold remediation process. If you have a mold problem or questions about mold, contact your local mold assessor.
