Then flash it with the shingles that you removed prior on both sides and above the vent.
How to install kitchen exhaust vent through roof.
Slide the vent under the shingles so they cover the top half of the vent flange.
Use a drill to make guide holes and then use a saw in order to complete the circle.
Nail the lower corners with roofing nails and tar the heads.
Apply asphalt roof cement to the bottom of the vent and slide in the vent under the shingles.
Bring the wire connectors flashlight vent hose tape and screwdriver.
The should cover the top of the vent flange.
If you have any questions or comments at all please comme.
Apply a bead of asphalt roof cement on the bottom of the vent.
Cover the hole that you are not using for exhaust and secure the hood to its final positioning to mark the location of the vent duct.
The lower part of the vent flange however will sit on top of the shingles.
Once you have it marked remove the hood and cut a hole in the wall or ceiling.
Remove the old hose from the wall fitting and attach the new hose using the vent hose tape.
Go to where the ceiling access hatch is located.
Be sure to extend the pipe up at least 2 to 3 above the roof to prevent snow buildup from causing problems.
Use roofing nails to nail the lower half of the flange in place at the corners.
Connect the ductwork with sheet metal screws wrap the connections with aluminum faced duct tape then wrap the attic part of the duct work with an insulated sleeve.
Vent through the roof.
Choosing a whole house fan.
The lower half of the flange sits on top of the shingles.
Install the vent and seal the underside of the vent flange with roofing grade sealant caulk.
Run duct work through the attic then attach the stove vent to a roof cap.
Screw the ductwork together.
This video is a comprehensive rundown on how to install a roof vent on a pre existing shingle roof.
You can buy the proper flashing to install it on a flat roof and a roof cap that has screen around it to prevent insects from entering.