DIY Network

How to Vent a New Flue

Once a new flue has been installed the next step is to connect it to the water heater in the basement. The following steps show how to install a fire stop and vent a flue and water heater.

More in Remodeling

install fire stop and vent flue and water heater
  • Time


  • Price Range

    $50 - $100

  • Difficulty



Step 1: Install a Fire Stop

In the basement, a fire stop is required at the ceiling and floor lines. In case of fire, the stop will prevent the fire from spreading into the wall cavity. Install fire stop sheet metal to close off the opening around the flue completely.

installing a fire stop in the basement

Step 2: Vent the Water Heater and Furnace

To vent the water heater and furnace properly, a directional, or Y, connection is needed. The new pipes and connectors should have double-wall insulation (Image 1).

Note: Use twist-lock pipe fittings to make the job easier.

The connection from the water heater to the new flue should have a 12" rise from the water heater and connect at a 90-degree angle to ensure proper ventilation (Image 2).

To relieve some of the weight from the pipes, install metal straps at the elbows for support (Image 3).