Installing Bathroom Fan Through Roof

A single exhaust exits through the roof figure a.

Installing bathroom fan through roof.

You mount a switch in each bathroom. Draw a mark on the bathroom ceiling where you d like to install the vent fan. The 2nd bathroom vent drips on the floor and is ruining the ceiling. Start in the attic and drill a hole through the roof in the desired vent location.

From the roof find the nail and use the utility knife to cut roof shingles from around the nail. You can use the existing switch wires and ductwork. For optimum performance locate it between the shower and the toilet. The master bathroom and the 2nd bathroom vent through the roof and through the same opening.

Also it helps to get a fan that s the same size as your existing fan so you won t have to adjust the size of the ceiling hole. Use an extra long 3 8 inch diameter spade bit to bore a reference hole through the ceiling and into the attic. The 2 pipes one a 4 master and the other a 3 2nd do not go through the ceiling but into a common box that goes through the roof. From up on the roof use a jigsaw or reciprocating saw to cut a 4 in.

Use the information below to select a fan. Try to keep it close to the fan location. Wrap the joints with duct tape. This setup requires an in line centrifugal fan mounted in the attic drawing air simultaneously from both bathrooms see photo.

Center the nail between two rafters. Leave the drill bit sticking through the roof so you can find the hole. Climb into the attic and clear away any insulation from around the hole. The installation is easiest if you re replacing an existing fan.