Once a scan confirms liner damage, you’re at a fork with real money on both paths. The good news: this decision is unusually evidence-driven, the camera footage practically makes it for you. Here’s how to read it.
When repair-in-place makes sense
The profile: damage is localized, a cracked tile or two, a failed joint section, in a liner that’s otherwise sound and correctly sized. The methods: heat-rated sealant systems for joints and minor cracks, or cast-in-place resurfacing that coats the flue interior with fresh refractory material, essentially a new liner surface inside the old structure. The appeal: targeted cost, preserves original clay construction (relevant on historic work), and done well it’s a durable fix, not a patch.
When replacement is the honest answer
Systemic cracking, damage at multiple heights means the liner as a system is done; repairing five sections of a failing whole is paying retail for a wholesale problem
Post-fire damage,
thermal shock cracks in a distinctive multi-tile pattern; the unseen damage travels with the seen
End-of-life clay, 40-50 year old tiles shedding and powdering aren’t a repair candidate, they’re an era ending
Appliance mismatch, new insert or fuel change needing a different flue size anyway,
reline once, correctly sized, instead of repairing the wrong diameter
Modern replacement is typically a stainless steel liner run down the existing flue, insulated, connected, capped, a one-to-two-day job that resets the liner clock by decades, with material options here.
The math that surprises people: repair quotes and reline quotes sometimes land closer than expected, especially when repair needs multiple access points or repeat visits. When the gap is small, replacement usually wins on lifetime value: new system, transferable documentation (buyers’ inspectors love it,
sale-time story), and the subject closed for a generation. We quote both paths when both are viable, fixed and written, and tell you which we’d pick at your address.
Start with the scan.
