Also be sure to place your kitchen vent at least 5 feet upwards from the eaves of the roof.
Venting kitchen exhaust fan through roof.
On the outside you will see the wind baffle that prevents snow from blowing in.
Venting through a roof vent or exhausting them in the attic could cause moisture problems and rot.
Use a proper roof top exhaust hood if you must go through the roof.
Vent your bath and kitchen exhaust fans through the roof through a special roof hood.
If you want to replace the range hood and exhaust fan above your stove and vent it to the outside and the stove is against an interior wall you have several options.
Yes you can vent a range hood through the roof using a 6 single wall pipe.
The duct for your exhaust fan needs to be run to the outside of the house to remove the chance of a fire hazard.
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.
But the rule of thumb is to route it the shortest and straightest path to daylight.
Here you see a very good roof top exhaust hood made by ventilation maximum in quebec where they tend to make roof vents taller to avoid being buried in the snow.
In either case do not vent into the wall or the attic.
Vent through the roof run duct work through the attic then attach the stove vent to a roof cap.