It is essential to properly vent range hoods, so that smoke, fats, vapors, and grease produced when you cook your food at home do not create a settlement and unsightly stains on the ceiling of your kitchen.
Range hoods are typically vented using a duct work that runs through the roof, and less often, through the outside exterior walls of your home. The duct work is usually concealed in the walls, and it is really important to make everything air and water tight. This way, you won’t have to come back to fix things after everything is set and done.
How to Vent your Kitchen Hood through the Roof:
If you are adding a new range hood over your stove, and plan to vent it out through the roof, you will need to get an adequately sized duct that will run all the way up through the ceiling into the attic and all the way up through the rooftop where it will be connected to your roof-top vent. Installing a new roof vent will require either hiring a roofing contractor to install it, or doing it yourself provided that you are handy, and can exercise proper safety precautions while on the roof.
Most common duct work is 10″ wide and shaped in a round accordion-like duct fashion. Yow will also need a same size roof vent (10″ opening) – preferably made with painted steel, and not plastic. First, specify a location for the roof vent between two rafters, and at least 3 feet away from a nearest roof protrusion, such as bathroom vets, skylights, chimneys, and most definitely, away from your roof valleys.
Note: An improperly installed roof vent can cause numerous roof leaks in your home, which would require a roof repair to address the problem caused by a faulty roof vent installation.
Also, be sure to place your kitchen vent at least 5 feet upwards from the eaves of your roof. That is five feet upwards along the slope of your roof, and away from the bottom edge.
Once a proper location for your roof vent is identified and marked, drill a hole through the roof, from the inside of the attic, located in the center between two rafters. Once you drill the hole, you will need to cut an adequately-sized opening to fit the range hood vent (either square or a round-shaped one, depending on the design of your roof vent).
After the hole is cut-in, remove the roofing shingles on both sides of the roof opening, and at least 3 rows above the opening. This way you can properly flash your kitchen hood vent.
Install the vent, and seal the underside of the vent flange with roofing-grade sealant / caulk. Then flash it with the shingles that you removed prior, on both sides, and above the vent. Seal between the top of the vent flange, and at the bottom of the roofing shingles, as well. That’s it – all you have to do now is connect the accordion duct to the roof vent.
The pictures we have provided here, demonstrate kitchen hood vent installation work on a metal shingles roof. The procedure for metal roofing shingles is nearly the same as it is for the asphalt roofing shingles, but it is much easier to work with asphalt shingles. Therefore, if you happen to have a metal roof installed on your home, then we strongly recommend that you hire a metal roofing specialist to do this job. Regular roofers are not capable of doing this work most of the time, and will cause many problems to your metal roof.
Installing range hood vent through the outside wall:
The procedure is similar to the installation of the kitchen hood vent through the roof, but it is, slightly different, though.
We will assume that you have a vinyl siding installed on your house. for other types of siding the installation steps are very similar. You will need same accordion duct work, and a vinyl vent. You can use a drier vent instead, but it might be too small – a typical drier vent is just 4″ wide.
Get a vinyl mounting box in a size of 12×18″, and cut a round hole in it of the appropriate size for the duct work. Then, attach the vent unit to the mounting box with long flat-head screws about 2-3″ apart, all around the perimeter. Apply some clear roofing-graded / exterior caulk to make a seal between the mounting box and the vent. Trim the flange on the vent to fit the mounting box size. Once the vent is installed and sealed, attach the accordion duct to it, and you are all done!