Throat-Mounted Round Fireplace Damper Installation

Remove ashes, old wood and the wood grate from the fireplace. It is necessary to get into the fireplace to install the damper. Lay plastic sheeting in the bottom of the fireplace to help protect your clothes.

Measure from the bottom of the chimney up 12 inches with a tape measure. You may need an assistant to shine a flashlight into the chimney if there is a sharp turn from the lintel at the top of the fireplace to the chimney. Make a mark on one side of the chimney at the measurement with a pencil. Repeat for the opposite side of the chimney.

Draw a straight line on the inside chimney wall with a pencil and straightedge at the marks on the two opposing sides. Make marks on each side 2 inches in from each corner. The top of your brackets will attach at these marks.

Place a bracket over each of the 2-inch marks, with the top of the bracket even with the line. Mark the bracket mounting holes with a pencil. If the damper has molded brackets, hold the damper body even with the lines on the chimney and mark the bracket mounting holes.

Insert a masonry bit into your drill that is the same diameter as the nail anchor. Nail anchors look like threaded nails with an aluminum anchor, similar to a plastic wall anchor. Place a piece of bright-colored tape around the masonry bit, 2 inches from the end. The tape serves as a depth marker.

Drill holes at each of the bracket mounting marks on the inside of the chimney. Drill to a depth so that the tape on the bit is at the chimney surface. Blow brick and masonry dust from the holes with a can of compressed air.

Position the brackets over the mounting holes and set the nail anchors through the brackets and into the holes. Hit the head of each nail anchor with a hammer to seat the anchor inside the chimney bricks. The nail head should be flush against the brackets. If the damper has molded brackets, you may need a helper to hold the damper while you install the nail anchors.

Hold the damper in a vertical position, if your damper is separate from the brackets. Insert the damper through the chimney, past the brackets. Reposition the damper so that it is horizontal, and place the damper body on top of the brackets. Make sure the damper chain extends downward.