Water Heater Vent Roof Clearance

Basement finishing projects are notorious for this code violation.

Water heater vent roof clearance.

In direct vent applications this clearance distance must be in compliance with local building codes the requirements of the fuel gas supplier for the heating appliance in use and the appliance manufacturer s instructions. Furnace water heater vent pipe clearance double wall typical listed and labeled double wall vent pipe clearance to combustible materials is one inch but you should always check before installation. Maintain the recommended air space clearance to combustible materials and building insulation. Atmospheric venting refers to a system in which exhaust from the water heater naturally rises out of the appliance s combustion chamber then travels up through a standard chimney style flue.

Cut a hole through the roof and interior ceiling to accommodate the vent pipes. If you are using a b vent typically a double walled air insulated vent for gas appliances typically you ll see a fire clearance stamped right into the metal of the chimney stating 1 inch minimum clearance to combustibles as you ll see in this photo. Water heaters with power venting come with an electric blower fan often very quiet installed on top of the water heater and can have either vertical or horizontal vent ducts. Since the vent does not rely on the buoyancy of hot air it can be run horizontally to the outside of the house.

Single wall vent pipes cannot pass through a ceiling floor firewall or wall. Use cleaner primer and pvc cement where the vent pipes join the water heater. Except for flat and very low slope roofs such as those listed in the table below b vents should be at least two feet above the roof surface as well. The top of the chimney should be at least two feet above anything within a ten foot radius of the chimney.

See the detailed b vent chimney rooftop clearance table below. Maximum horizontal section of the furnace water heater double wall vent pipe cannot be longer than 100 of the vertical vent pipe length. 6 minimum clearance from single wall vent pipe or flue vent connector to any combustible material. For gas fired water heater vents.

Metal vents that are too close to wood or combustionable materials may cause the wood to burst into flames. Single wall vents get very hot requiring a 6 in. For non direct vent applications that is side wall venting only the required clearance is 7 feet. Cut away the wood that s too close.

Single wall vents should have a minimum of 6 inches of clearance and double wall sometimes called a b vent should have 1 inch minimum clearance.