Some builders mistakenly allow the fan to blow moist air into the attic a practice that simply moves the mold problem to another part of the house.
Mold in attic from bathroom fan.
Mold needs 3 things to grow.
This is a different perspective from the other video about bathroom fan venting causing mold.
Moisture and mold in the attic if your bathroom fan exhausts into your attic and not outside of your home you could start having serious issues with moisture and mold.
Moisture food and warmth.
Dryer exhaust vents kitchen exhaust fans and bathroom exhaust fans are designed to pump moisture out of your home.
Surviving mold in your attic venting a bathroom fan into an attic my detailed home ventilation won t prevent attic mold growth healthy indoors home inspection finds bad bathroom fan venting le to moisture where does the bathroom fan take all air quora.
Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems.
Dryer vents plumbing vents kitchen or bathroom fans vented into the attic.
Telltale black mold stains typically result from this ventilation error.
Also plumbing stacks in the attic can be a source of condensation which can lead to attic mold growth.
So make absolutely sure that they terminate outside your home and never in the attic.
For bath fans it is important to insulate around the vent pipe exiting the fan to prevent moisture from condensing inside the pipe.
The vacuum is then covered by air from the basement and crawl space that contains impurities like dust mites mold spores and odors.
Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons.
If you eliminate just one of these elements mold will starve and die.
In many cases moisture from bathroom fans is the primary source of attic mold infestation.
When warm air rises in your home it escapes through the attic leaving a vacuum behind.
Related to 3 above this practice can pump warm moist air into the attic where it can be trapped and begin the cycle of mold growth.
Http youtu be pne imqvfoy it shows the things we noticed to diagnose the bathroom fans venting.