Bathroom Exhaust Vents Into Attic

While it was once acceptable to vent bathroom fans into the attic space near a roof vent this creates conditions that leave the attic susceptible to mold and other issues.

Bathroom exhaust vents into attic.

Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons. No bathroom fans should vent into the attic. However you can vent a bathroom fan through an attic while it terminates on the roof or gable end. It may also violate a shingle warranty.

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. Through the roof or an exterior gable wall. It s all outdoor air anyways right. 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.

In my area building code clearly stats that exhaust fans must not vent into the attic. Not too sure what the old building code was but if the new building code states to vent bathroom fans outside it has its reasons behind it. Options for venting a bathroom exhaust fan include best to worst. Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems.

Excessive moisture will cause condensation on roof members and insulation. By saum hadi posted on february 28 2020. It seems like such an easy solution just leave a bathroom vent hose in an attic. No you cannot vent the bathroom exhaust fan into the soffit vents.

If you put the bathroom exhaust vent to close to the soffit vents it will get drawn back into the attic where it will condense and have the same issues occur as above. One person suggested that we can vent it to the soffit of the house but i dont see why it should be that way as it is used for drawing in air from outside and keep the air moving in the attic to breathe. Bathroom exhaust fan venting into attic. Moisture frost mold etc.

They need to vent outside. It s never okay to vent directly into the attic even if you re attic is vented. No you should not vent a bathroom fan directly into an 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.

To be properly terminated bathroom fans should exit the home through stem vents that are specifically used for this purpose. Bathroom exhaust venting into attic so we just discovered that our bathroom exhaust is venting into the attic and it is disconnected. 5 reasons bath fans have such poor air flow bathroom exhaust fan venting code basics venting a bathroom fan into an attic attic bathroom vent fan exhaust.