How to Install a Chimney Damper

smoke drifting out of a chimney on a roof
  • 1-4 hours
  • Intermediate
  • 400-500
What You'll Need
Chimney damper
Protective gloves
Silicone sealer
Utility knife
Special adhesive
Caulking gun

A chimney damper is usually located around the open area connecting the chimney to the firebox. They prevent heated air from going out of the house. While maintaining heat inside the chimney, dampers also serve as protection from external elements, preventing cold air and even rain from getting inside the chimney. If they are not in use, it is important to keep them shut.

Several types of chimneys associated with gas and wood-burning use dampers. There are cases wherein the “chimney effect” will force more heat outside rather than inside the house. This is where the importance of a chimney damper installation comes in. While most people think chimney damper installation is hard, it is in fact relatively easy as there aren’t as many special tools to use as people think.

Wear protective gloves as you work. Note there are different ways to install chimney dampers as it depends on the kind of chimney damper used.

1. Single Chimney

fire burning in a fireplace

For a single flue, the chimney damper easily slides onto the flue. The damper should be able to cover about one to three inches of the chimney’s outlet. Using a screwdriver, tighten the position of the damper with screws.

2. Round Tile Chimney

For a chimney damper that has an inside mount orientation, all you need to do is to push it down towards the location of the flue. It should have a firm friction fit. The chimney damper is secured using a silicone sealer. Make sure that all sides are sealed.

3. Metal Chimney

metal chimney protruding from a roof

A chimney damper with an inside mount orientation is installed in the same way as with round tile chimneys. The only difference is that the chimney dampers are not sealed using silicone. Instead, a different kind of adhesive or screws is used. The same adhesive is used to seal chimney dampers with top mount orientation. The following steps provide a guide on how to use the adhesive while installing chimney damper.

Step 1 - Prepare the Chimney Damper

Before applying the adhesive, position the chimney damper directly over the area of the chimney where it is to be installed. Try to make adjustments or tight fit the damper to see how it looks. It should be fitted right into the outlet.

Step 2 - Mark Perimeters

Mark a line near the border of the flange. Use a caulking gun to place around 3/8-inch thick coating of adhesive. Apply adhesive from one end of the side to the next end. The wave of the line should measure around one inch from one end to another. The line of glue should represent a gentle wave.

Step 3 - Position the Chimney Damper

Position the chimney damper over the outlet and then apply pressure. A utility knife may be used to remove the excess adhesive on the sides.

To make sure that the chimney damper is properly installed, it’s best to consult an expert post-installation.