Options For A Damaged or Missing Flue Liner
An unlined masonry chimney flue.
A chimney with a damaged or missing flue liner is potentially hazardous. Creosote can collect in rough spots in raw masonry, or in gaps between flue tiles, where it can form unsweepable deposits which can eventually ignite. Also, exhaust gases and/or heat can pass through the uninsulated masonry or the gaps between tiles and potentially enter the home. Barnhill Chimney Company cannot recommend using chimneys with damaged or missing flue liners.
Fortunately, if you have a chimney with this problem, there is hope! We offer four general options for working with damaged or missing liners:
A gap between terra cotta flue tiles.
- For a traditional, open fireplace
- This option coats the inside of a damaged terra cotta flue with a thick layer of insulating mortar, creating a new, smooth and insulated flue. Chimneys which have no liner at all can receive a historic HeatShield reline, which consists of two HeatShield applications separated by a heat-resistant membrane.
- Wood burning insert
- For an efficient heating option with wood
- A wood burning insert is a large metal box which slides into a masonry fireplace. A flexible stainless steel flue liner runs from the insert out the top of the chimney — this effectively bypasses a damaged or missing flue. Some fireplaces may not be able to accommodate an insert or steel liner due to size or construction restrictions.
- Direct vent gas insert
- For an efficient heating option with gas
- A direct vent gas insert is a large metal box which slides into a masonry fireplace. From the insert, two smaller stainless steel flexible liners run to the top of the chimney, effectively bypassing a damaged or missing flue. These two smaller liners can sometimes fit in a flue where a wood burning insert’s larger liner cannot.
- Vent-free gas logs
- For a primarily decorative fire
- Vent-free gas logs bypass a damaged flue entirely — we simply block off the chimney at the throat with a throat seal and install the logs under that. This is generally the cheapest option for continuing to use a chimney with a damaged or missing flue liner. Vent-free gas logs should be considered primarily a decorative fire — although they do get warm, they use room air to burn and should not be run for extended periods of time.
The option you choose depends primarily on what you want to get out of your fireplace: a traditional wood fire, an efficient heating option, or an “occasional” fireplace which fits smaller budgets. All of these options have their good points. Our technicians will be happy to examine your individual fireplace and chimney system and recommend something that will work for you!
Please note that the above options are designed for masonry chimneys. Prefabricated and stove pipe chimneys are made from metal pipe which usually has two walls, an inner and an outer wall, and serves as its own liner. If these chimneys fail, usually the best recourse is to install a new pipe chimney. If you are in doubt, schedule an inspection with one of our techs, who can make sure you and your chimney both have the same ideas.
