Mold grows in attics due to four main reasons.
1. Warmer temperatures
2. High humidity, condensation, or major water intrusion from a roof leak
3. Improper ventilation, no ventilation, or blocked vents
4. Lots of food (insulation, wood, dust, stored household items)
SIGNS YOU HAVE MOLD IN THE ATTIC
In no particular order, here are 8 common signs of attic mold.
1. Water stains on your ceiling. This could be from a new or old leak but any water staining should be investigated.
2. Water dripping from smoke detectors, light fixtures, bathroom exhaust fans, and ceiling fans. This is a sure sign that the attic has a level of moisture that needs to be addressed. Mold growth is highly likely.
3. GFI outlets tripping regularly for no apparent reason. If your plumbing is in the attic and begins to leak or you have a roof leak, often times it will come through the attic, down the wall, and begin to trip the GFI outlets.
4. Wet insulation in the attic. Attic mold loves wet insulation. In fact, it often times take only 12 hours for certain types of insulation to start growing mold. This is why mold resistant insulation is so important in an attic.
5. Dark black staining on wood surfaces in the attic. A lot of remediation companies write off darkened wood on beams in the attic as “aging.” Sure, wood can change color a bit as it ages but aging wood in the attic doesn’t develop dark patches here and there. If you see dark brown or black areas on the wood, chances are you have mold in the attic.
6. Attic feels very hot or stuffy. When attics are properly ventilated, they should have the feel of a gentle (but warmish) breeze. When an attic is stuffy, that indicates you have a ventilation problem, which often results in mold problems.
7. A musty smell in the attic. Sure, mold can smell like a lot of things but an attic with mold will always have a pretty musty type odor.
8. Frost buildup on the underside of the roof sheathing in winter. When it’s cold enough outside, water vapor in an attic with improper ventilation can freeze on the underside of your roof. While this is easy to spot, by the time you see it mold may have already begun to grow.