How to Re-Line an Old Fireplace

Remove the existing fireplace cap, if applicable. Shine the flashlight into the flue to determine if there is an existing tile liner inside. Remove any tile liners using a power drill fitted with a gladiator (this will make a huge mess in the house). Clean the debris in the fireplace before proceeding.

Crawl inside the fireplace and shine your flashlight up through the damper. Look for a ledge on either side of the fireplace past the smoke chamber -- this is where the flue liner should rest. Measure the full width of the flue as well as the width of the ledge. Take this opportunity to measure the flue from the ledge up through the end of the masonry chimney with the help of a friend standing on the roof.

Take the measurements to your fireplace supply company and use them to order a flue liner. It may help to also measure the opening between the fireplace and the room where it is located to determine if the new flue will be sized correctly for the fireplace.

Construct the flue liner on the ground according to manufacturer's directions. Add any insulation blankets included in the package. Carefully hoist the flue liner to one or more friends on the roof. Climb onto the roof and help position the liner directly above the flue. Slowly lower it onto the lip just before the smoke chamber.

Go inside the house to insulate the bottom of the liner. Remove the damper if possible, or open it to its widest setting. Insert small pieces of batt-type insulation into the gaps between the liner and fireplace (if your liner is uninsulated) to create a plug for the insulation mixture. Pour the pre-mixed flue insulation into the chimney from the roof, filling the space between the masonry and the liner.

Lay a bead of caulk where the top plate will sit on the top of the flue. Fit the plate over the extruding section of liner and push it firmly into the caulk. Install the chimney cap over the liner according to the directions in the kit, being sure to screw it firmly to the flue liner.