There are several possible reasons to reline a chimney:
- In houses built prior to the 1950s, masons often did not use terra cotta flue liners. Please see our glossary of terms page for more information on the dangers of unlined flues.
- When a wood stove is hooked into a thimble, (a round opening where a woodstove connects to a masonry chimney, usually made of terra cotta or metal) directly into a terra cotta lined chimney, sometimes the flue is too big for the appliance to draft properly. For specifics, please see our glossary page.
- Wood stoves or wood stove inserts installed in fireplaces should have a full liner all the way to the top of the flue. A direct connect, on the other hand, is when an insert or a woodstove is installed into a masonry fireplace without a full liner. See our glossary of terms page for a more thorough explanation of this installation type.
- Occasionally, because of a chimney fire, earthquake, or age, terra cotta flue tiles develop cracks that render the chimney unsafe to use without being relined, either with a stainless steel liner, a poured refractory liner, or the HeatShield® system. Vertical cracks in a chimney flue are usually caused by heat expansion and contraction, as often occurs with chimney fires. Horizontal cracks are usually caused by physical movement, such as an earthquake.