This is due to the Stack Effect.
The Stack Effect, a.k.a. the Chimney Effect, is the upward movement of air in your home. As air warms, it rises. So, as the air in your basement or crawl space warms, it cycles through your home.
Any particles that are lighter than air - like mold spores and humidity - will also be cycled through your home.
So, how do you know if you have a mold problem?
Mold detection tips:
According to the CDC, all types of mold should be considered equally when evaluating your health risk. If you notice any of the items listed below, chances are good that you have mold in your home.
- Musty or moldy smell in your home
- High indoor humidity
- Moldy, chalky patches on the floorboards or wall
- Health problems: sore throat, stuffy nose, eye irritation, rashes, wheezing or shortness or breath, and even lung infections!