Flue liners have been required by code since 1927, yet many homes built prior to 1950 do not have liners. Flue liners are installed to provide a complete sealed exit for toxic flue gases.
Many chimneys without clay liner or with cracked or otherwise damaged liners can often be made safer by installing a U.L. listed stainless steel chimney liner system.
Stainless steel chimney liners repair damaged or missing clay terra cotta liners.