Why Bathroom Fan Vented Into Attic

Venting the fan into the attic can cause many issues because of the moist air the fan removed from the bathroom.

Why bathroom fan vented into attic.

Home builders learned from this lesson and began running exhaust ventilation ducts to the outside of the home. This can not only cause mold but damage to your roof system. Dumping bathroom exhaust into an attic or under roof space invites costly mold contamination frost under the roof in freezing climates moisture damage to roof sheathing possibly even plywood delamination or rot roof failures and shorter roof shingle life. A common defect found in many homes is a fan that exhausts into the attic space.

Historically extractor fans were vented into the attic of the home. This moist air will cause condensation on the surfaces in your attic. However you can vent a bathroom fan through an attic while it terminates on the roof or gable end. Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems.

Bathroom exhaust fans perform an important function by removing excess moisture from your home. For this to work properly air ducts must be properly sealed meaning no tears or holes that would allow moisture to escape into the wrong spots. It is because of this that many builders tend to advise against this method. This involves running ductwork from the fan usually though an attic and out through the roof.

In order to accomplish this the roof has to have a hole cut in it. When venting a bathroom exhaust fan make sure to vent the air to the outside rather than into your attic where it can cause mold and mildew to form. If you allow the air from your bathroom exhaust fan to mix with the air in your attic which is usually the same as the outside temperature it can cause condensation wetting the wood allowing for mold growth and over time weakening the structure of your home while causing possible health issues for your family. This can cause a significant problem because it allows moisture to accumulate and encourage mold growth.

Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons. Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof. It seems like such an easy solution just leave a bathroom vent hose in an attic.