Terracotta flue liner tiles and joints are subjected to heat, cold, moisture, expansion/contraction, corrosives, and sometimes a hostile chimney fire. These components can crack & deteriorate the tiles, leaving a breach in their intended purpose. We use a UL listed system (HeatShield®) to repair/restore most flue systems at a fractional cost of relining. However, some systems are just too far gone for this process and must be relined.
Getting a woodstove insert involves more than you would think. Just take a look at our chimney repair and rebuild section.