In some instances a fireplace can be relined by using a product called HeatShield®. HeatShield® is a specially formulated “Cerfractory®” sealant material that restores the integrity of the chimney’s flue for the proper venting of flue gases. In several instances, it can be a less costly alternative to relining with stainless steel.
In our experience, we have found HeatShield® to be a great product. However, it cannot be used in all situations. For example, if the flue has any creosote in it that cannot be removed (either manually or with chemicals), the creosote would prevent the HeatShield® coating from properly adhering to the clay flue tiles. In addition, the clay flue tiles have to be structurally sound and have the ability to withstand the pressure of the HeatShield® application. A flue that has multiple angles, in our opinion, would not be a good candidate for this product, as the multiple angles can oftentimes prevent a smooth, even coverage of this product.