How to Seal a Fireplace Flue

Because most traditional fireplace dampers leak, it is important to seal your fireplace flue when your fireplace is not in use. Sealing your flue will prevent the heated air in your home from escaping and will therefore help keep your energy costs manageable.

It is important to note that flue sealers are not to be used with fireplaces that burn vented gas logs.

Commercially Available Sealers

  • Specialized Dampers
  • Inflatable Flue Sealers

Step 1 – Decide What Manner of Flue Sealer You Need

Specialized dampers with silicone rubber seals are now available, and they are far more efficient than traditional dampers. They can be opened and closed at will.

Inflatable sealers serve as chimney stoppers. They are far less expensive than the newer dampers, but they must be removed before every fire and cannot be reinstalled until the fireplace has completely cooled.

Step 2 – Purchase Your Flue Sealer or Flue Sealing Materials

Flue sealers can be found at chimney supply and masonry stores and can be purchased from many online retailers.

Step 3 – Install Your Sealer or Sealing Material

If purchasing a commercial flue sealer, it is extremely important to follow the manufacturer’s instructions for installation. Only the manufacturer can instruct you in the safest method of installing your flue sealer.