The range hood is only half of the equation when it comes to getting the smoke and odors out of your kitchen. The other half is the venting that exhaust smoke and fumes from the inside to the outside. With proper planning and materials, homeowners can safely vent their cooktop range hood through the roof and keep their kitchens clean and bright.

    In this article, follow my step-by-step guide for venting a range hood through the roof, as well as maintenance tips based on my experience as a professional roofer and carpenter.


    1. Evaluate the Range Hood Location

    First, assess where your range hood is located relative to the roofline directly above it. The ductwork path should be as straight and short as possible to optimize airflow. A general rule of thumb is a stove requires 10 cubic feet per minute (CFM) of airflow for every inch of stove so a 40-inch stove will require 400 CFM of airflow. 

    Most single-story house and kitchen setups allow for vents to run directly from the top of the stove, through the attic, and to the roof. If this isn’t the case for your home or if you have a two-story home, don’t worry — you can bend and reroute ductwork as needed. The airflow CFM may need to be oversized to compensate for a non-straight path, but it is possible. 

    2. Select the Right Vent Cap

    Once a vertical route looks achievable, choose an appropriate roof cap. The roof vent cap fits over the ductwork where it penetrates the roof. The cap should allow for proper airflow; block rain, snow, and debris from entering; and prevent rodents and insects from accessing ducts.

    Range hood vent caps come in different styles. Here are common range hood vent cap varieties:

    • A curb cap has ductwork flush with the shingles. A raised “curb” secures it to the roof deck, and it often uses a backdraft damper.
    • A roof jack cap has flashing that fits under shingles to integrate the duct exit point. The cap fits over the flashing.
    • A standard vent pipe cap is a basic end cap that covers the protruding ductwork with mesh mesh screens to deter pests.

    3. Install the Ductwork

    Once homeowners map out the route and select the vent cap, it’s time to start installing the metal ductwork. Use smooth metal hard pipe or flexible aluminum HVAC ductwork designed for range hoods. Get the right duct diameter — usually 6-inch for residential hoods.

    Follow these ductwork installation tips:

    • Fasten all joints with sheet metal screws and use duct tape as an extra precaution to seal joints.
    • Caulk around the duct’s exterior flange at the vent cap base at side walls.
    • Support ducting from above so weight doesn’t put strain on the connections. Use metal straps to secure framing.
    • Use long-radius elbows for any necessary turns, avoiding sharp 90-degree angles.
    • Weatherproof exterior holes using flashing and sealant.

    Proper materials and following the manufacturer’s instructions provide safe roof venting. Make sure to seal any unused ductwork openings which offer pests a way inside.

    4. Maintain Roof Vent For Optimal Performance

    Over time, debris and residue can accumulate in the venting system, hurting airflow. To maximize ventilation, do the following:

    • Check that duct supports and straps aren’t loose or sagging. Re-tighten any loose hardware.
    • Inspect any mesh screens in the roof cap for damage or clogs. Clear debris using pressurized air and replace damaged screens.
    • Look for gaps or leaks at duct joints, seals, and roof flashing. Re-tape and re-seal as needed.
    • Periodically detach and clean ducting joints. Use a degreaser and hot water to remove grease buildup.
    Today’s Homeowner Tips

    With proper maintenance, such as cleaning your range hood filters and regularly inspecting vents for damage, your roof-vented range hood should deliver years of reliable ventilation. If debris and buildup is excessive or you notice major gaps/leaks, it may be time to replace the ductwork.


    So, Is Venting a Range Hood Through the Roof a Good Idea?

    Roof venting for range hoods works well, especially when other routes are constrained. It prevents exterior wall penetration while providing a direct outdoor path to improve indoor air quality.

    There are some downsides to venting through the roof, though. It’s harder to access vertical ducts in attics to clean them; vent caps may experience damage in snowy, icy, or stormy climates; and roof holes can bring leak risks that require weatherproofing and upkeep.

    However, with smart range placement, quality materials, and robust weatherproofing, roof venting can be an effective solution.


    FAQs About Venting a Range Hood Through the Roof

    How high should the ducting extend above the roof?

    Most building codes mandate that the ducting protrude at least 12 inches above the roof surface. In heavy snow regions, extending 24 to 36 inches above the roof prevents snow buildup from blocking the cap.


    How difficult is installing roof flashing?

    Proper flashing installation involves removing shingles, fitting the base over roof decking, and integrating it back into the roofline. This complex process is best for roofing professionals unless homeowners have relevant DIY experience.


    What duct size is recommended for range hoods?

    For most residential kitchen range hoods, 6-inch diameter ductwork is sufficient. High-powered restaurant-grade range hoods may need 8-to 10-inch ducting. Consult the range hood manual for the recommended size.


    Should ducting be insulated in unconditioned attic areas?

    Insulating ducts help minimize cold weather condensation. I suggest fiberglass wrap or foam insulation with a minimum R-6 rating for range hood ducts in an unconditioned attic.


    Is vertical or horizontal ductwork better?

    Vertical routes are best in order to reduce grease accumulation and optimize airflow. Limit horizontal sections to the shortest lengths necessary, sloping them upwards so grease drains back into the hood.


    Editorial Contributors
    avatar for Doug Sluga

    Doug Sluga

    Doug Sluga is a professional roofer and carpenter with ten years of experience in residential and commercial construction. His expertise spans the breadth of the roofing trade from minor repairs to laying shingles to framing trusses. These days he spends most of his time writing about roofing and the roofing industry.

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    photo of Lori Zaino

    Lori Zaino

    Lori Zaino is a freelance writer and editor based in Madrid, Spain. With nearly two decades of editorial experience, she’s written and edited for publications like Forbes, CNN, Insider, NBC, Newsweek, The Points Guy, The Infatuation, and many others. Having just completed her first home renovation, she’s more interested in home improvements than ever, dedicated to bringing you fresh and accurate content to help you update your living spaces.

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