How to Make Vents in a Bathroom

Turn off the electricity to the bathroom using the house’s electrical panel. Measure the dimensions of the bathroom vent, and then draw an outline of the vent on the bathroom wall, using a pencil. Drill a hole in the middle of the outline you drew.

Climb into the attic and locate the hole you drilled to see if it sits roughly halfway between two joists in the attic. If not, drill a second hole that does sit between the two joists; measure the change in position between the two holes, and change the position of the outline you drew on the bathroom ceiling.

Cut along the lines of the outline you drew on the ceiling using a jigsaw. Climb into the attic with the bathroom vent assembly and carefully lower it into the hole you cut in the ceiling.

Slide the metal brackets that came with the vent into the tabs on the sides of the vent assembly. Pull on the brackets to extend them, stopping once they touch the nearest joists. Drive a screw through the end of each bracket and into the joist the bracket is touching, anchoring the vent assembly into place.

Pull the free electrical wiring through the opening on the side of the vent’s electrical box, and then tighten the screw in the box’s opening to hold the wiring in place. Pull off the insulation from the ends of the wires on the house’s wiring as well as the wires from the vent assembly, using a wire stripper tool. Twist the bare wires from the same-colored wires clockwise together with your bare hands. Thread wire nuts onto the bare wires by turning them clockwise as well.

Position a 90-degree duct elbow onto the exhaust port on the vent assembly. Point the duct elbow’s opening straight up, and then wrap foil duct tape around the connection between the duct elbow and exhaust port to secure the connection

Climb onto your roof using a ladder. Hold the duct end of your bathroom vent’s roof hood against the portion of the roof where you have decided to install it. Trace around the roof hood's duct using a marker. Remove the duct and cut out the tracing with a jigsaw.

Insert the vent hood's duct end into the opening in the roof and trace where the hood sits on the roof's shingles. Remove the duct and vent, and ut out the roof shingles where you traced the vent, using a utility knife. Insert the duct on the vent hood through the opening in the roof and drive sheet metal screws through the sides of the duct and into the roof, holding it into place.

Apply roof cement to the joint between the duct and the roof’s surface. Position the vent hood onto the duct you installed in the roof, and drive roofing nails through the mounting holes on the hood’s flange. Spread roof cement onto the hood’s flange and press the shingles over the cement to hold them in place.

Slide the flexible duct hose over the 90-degree duct elbow and the duct anchored into the roof. Position the hose clamps over the connections between the duct hose and the ducts, and then tighten the screws on the hose clamps to secure the connection. Turn on the electricity to the bathroom using the house’s electrical panel.