Bathroom Exhaust Into Attic

If you vent the bathroom exhaust fan to close to the soffit vents which are vented plates under your homes outer edge and roof your home the air can be sucked right back into the attic from the soffit.

Bathroom exhaust into attic.

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. A bird s nest in a bathroom vent will greatly reduce or eliminate the effectiveness of a bathroom exhaust fan. Surprisingly bathroom fans are not required by some building codes. Bathroom vent fans are rated by how many cubic feet of air they can move in one minute known as the cfm rating.

All municipalities have different requirements but some do not draw a hard line on requiring exhaust fans. No you cannot vent the bathroom exhaust fan into the soffit vents. Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems. Bathroom code does address the issue of moving odor and moisture laden air from the bathroom to the outside.

It may also violate a shingle warranty. Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons. To determine which size fan to buy for your bath multiply the room s square footage by 1 1. In no case is it acceptable to just dump any exhaust fan directly into an attic.

Can you vent a bathroom exhaust fan into the soffit vents. It eliminates the need for routing ductwork through the house and these fans usually dry the bathroom more quickly. Anon if i understand your original question you have a bath exhaust that is discharging into a roof cavity or space not to outside. It s also important to note that if you install a roof vent cover for a clothes dryer you must remove the metal screen because it will catch lint and may turn into a fire hazard.

The bathroom here is below an accessible attic so tom ran the exhaust duct across the attic and out a gable end. 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. Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof.