Bathroom Exaust Into Attic

This section notes that air exhausted from the bathroom must be sent outdoors not indoors to the same residence or indoors to any other dwelling unit.

Bathroom exaust into attic.

Options for venting a bathroom exhaust fan include best to worst. Exhaust air from toilet rooms and bathrooms shall not discharge into attic crawl space or other areas inside building. 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.

Although this isn t always possible in attic crawl spaces you should always insulate the duct to prevent condensation problems. So what you want to do is you want to install a duct a vent duct and you can use flex duct for this. The bath should be vented by either a 20 cfm continuous vent fan or a 50 cfm vent fan that is intermittent or switched. In order to accomplish this the roof has to have a hole cut in it.

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. If you have two bathrooms that are close together and one has an exhaust fan and the other doesn t you might be wondering if you can tie a new exhaust duct into the existing one. Exhausting of the bath vent fan must indeed be to the building exterior. It may also violate a shingle warranty.

Through the roof or an exterior gable wall. That will take it from the bath exhaust fan to a discharge point. This involves running ductwork from the fan usually though an attic and out through the roof. Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof.

One attic mounted fan for two bathrooms one in line centrifugal fan can be mounted in the attic to exhaust the moisture from two bathrooms. An enclosed toilet would require its own exhaust fan exhaust fans approved for installation in wet areas would need to be located over or near the shower or tub bathroom doors should have at clearance to the floor. You can find 4 in. While this may seem obvious homeowners may out of convenience direct the vent into either of these locations.

The best exhaust fan venting is through smooth rigid ducts with taped joints and screwed to a special vent hood. Duct already wrapped in insulation at home centers.