Bathroom Exhaust Fan Vented Into Attic

You should never exhaust the bathroom fan directly into the attic.

Bathroom exhaust fan vented into attic.

Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons. Excessive moisture will cause condensation on roof members and insulation. However you can vent a bathroom fan through an attic while it terminates on the roof or gable end. Options for venting a bathroom exhaust fan include best to worst.

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. It may also violate a shingle warranty. Through the roof or an exterior gable wall. No you should not vent a bathroom fan directly into an attic.

This will cause mold and could leave your home unlivable. 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. Most municipalities require extractor and exhaust fans to be vented to the outside of the building with an vent cap. Your attic is not a temperature controlled environment is never the same temperature as your living space and generally closer to the temperature outside.

No you cannot vent your bathroom exhaust fan into the attic. It seems like such an easy solution just leave a bathroom vent hose in an attic.