Do It Yourself Insulation for a Chimney Plug

Set an extension ladder on the side of the house near the chimney. Ask your helper to hold the bottom of the ladder steady as you climb up to the roof. Examine the cap that covers the top of your chimney to determine how to remove it. Most caps have hex-head screws requiring a nut driver or socket wrench. Remove the screws securing the cap and set the cap to the side.

Measure the inside circumference of the chimney with a tape measure. Subtract 1 inch from the measurement and cut a piece of sheet metal to the measurement with tin snips. Add 2 inches to the measurement and cut a second piece of sheet metal to size with tin snips.

Drill two 1/2 inch holes next to each other through the first, smaller diameter piece of sheet metal with a drill. Drill two 1/2 inch holes next to each other on the larger diameter piece of sheet metal.

Fill three small garbage bags with batt insulation. Tie the bags closed. The bags serve as the insulation for the chimney while the smaller piece of sheet metal provides a floor inside the chimney for the bags.

Cut a 6-foot long piece of 1/2-inch rope with a utility knife. Take the two pieces of sheet metal, bags of insulation, rope and silicone caulk to the roof.

Insert one end of the rope through one hole on the smaller piece of sheet metal. Feed the end back through the second hole. Pull the end through so the rope is even and the sheet metal is at the center of the rope.

Set the smaller piece of sheet metal into the chimney with the rope ends facing you. The sheets metal should be past the roof line in the chimney. Hold the rope and push the bags of insulation into the chimney.

Apply a 1/2-inch bead of silicone caulk around the top of the chimney opening with a caulk gun. Insert the ends of the rope through the holes on the second, larger piece of sheet metal. Set the sheet metal on top of the chimney over the caulk. Tie the ends of the rope together.

Press down on the sheet metal to firmly seat it over the caulk. Apply caulk to the holes in the sheet metal where the rope enters. Reattach the chimney cap to the chimney.

Go inside the fireplace and open the damper. Fill three more small garbage bags with insulation and stuff the garbage bags into the chimney through the damper. Close the damper. This prevents your heated air from going through the chimney.