How to Mount an Undermount Microwave

Install the ductwork to vent the microwave. Mount the outside roof cap duct to the outside of your home by cutting a hole through the roof exterior with a saber saw. Slide the roof cap duct under the shingles and tack down with a hammer and finishing nails.

Run the round straight 6-inch diameter duct pipe from the roof cap down into the top of the cabinet through a hole cut with the saber saw. Cut the hole for the transition adapter duct through the bottom of the cabinet by following the template against the underside of the cabinet. Cut out the round hole for the electrical cord and plug.

Attach the transition pipe to the round 6-inch-diameter duct pipe. Seal all seams with aluminum tape.

Place a stud finder against the wall under cabinet. Locate a stud in the wall and place a mark with a pencil. Secure the microwave to at least one stud.

Attach the mounting plate to the wall. Place in the wood screw at the mark where the stud is located. Drill holes with the 5/8-inch bit and place in the toggle bolts and wings. Tighten the toggle bolts.

Drill holes for the microwave's top screws by following the top cabinet template. Open up the microwave's blower for exhausting upward into the duct by removing the screws with a Phillips screwdriver. Pull out the blower unit and turn it 90 degrees until the fan blades face upward.

Place the blower back into the microwave and set in the screws. Place on the exhaust adapter to the blower plate. Remove the tape from the damper to the exhaust adapter.

Mount the microwave onto the mounting plate while stringing the power cord up through the round hole. Secure the microwave with screws drilled down through the top cabinet. Adjust the exhaust damper so it lines up to the transition adapter duct and secure with aluminum tape.