Bathroom Fan Vent Exhausts Into Attic

Vent your bath and kitchen exhaust fans through the roof through a special roof hood.

Bathroom fan vent exhausts into attic. 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. Venting through a roof vent or exhausting them in the attic could cause moisture problems and rot. Bathroom exhaust fans perform an important function by removing excess moisture from your home. 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.

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. It may also violate a shingle warranty. Surprisingly bathroom fans are not required by some building codes.

No you cannot vent your bathroom exhaust fan into the attic. Two bathrooms one roof vent both bathrooms are vented by a single in line fan that has one exhaust vent running through the roof. However you can vent a bathroom fan through an attic while it terminates on the roof or gable end. In order to accomplish this the roof has to have a hole cut in it.

One in line centrifugal fan can be mounted in the attic to exhaust the moisture from two bathrooms. Your attic is not a temperature controlled environment is never the same temperature as your living space and generally closer to the temperature outside. Bathroom code does address the issue of moving odor and moisture laden air from the bathroom to the outside. Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons.

You should never exhaust the bathroom fan directly into the attic. It seems like such an easy solution just leave a bathroom vent hose in an attic. No you should not vent a bathroom fan directly into an attic.