Liner technology is a rare three-option market where each option genuinely owns a niche, the confusion only starts when someone sells their niche as universal. Here’s who owns what:
Clay tile: the incumbent
What it is: fired ceramic tiles stacked and mortared during original construction, the standard in most DFW masonry chimneys. Strengths: genuinely durable (50+ year service lives), corrosion-proof, cheap at construction time. The catch: retrofit is brutal, replacing tiles inside a built chimney means opening walls at every failure point, so when a tile system reaches end-of-life, the practical successor is usually one of the other two. Clay’s niche: new construction and historic restoration.
Stainless steel: the reline workhorse
What it is: a continuous or sectioned stainless flue run down the existing chimney, insulated, connected to the appliance, capped. Strengths: installs in a day or two without opening masonry, sizes precisely to the appliance (the draft-sizing job), handles wood, gas, or pellet duty in the right alloy and gauge, and quality liners carry lifetime transferable warranties, a genuine home-sale asset. The catch: quality varies invisibly; thin-gauge uninsulated bargain liners exist and underperform. Stainless’s niche: nearly every reline, which is why it’s the default answer.
Cast-in-place: the structural rebuild
What it is: refractory cement formed against the flue’s interior (via inflatable form or spin-cast), creating a new seamless liner bonded to the old structure. Strengths: simultaneously lines and reinforces, the play for flues whose tile and surrounding masonry are both marginal, and handles odd shapes and offsets that fight rigid liners. The catch: costs more than stainless in most cases and demands real installer expertise. Its niche: structurally-tired chimneys worth saving without rebuilding.