Why liners fail
- Cracked clay tiles. Most older masonry chimneys are lined with clay flue tiles. They crack from age, from a chimney fire (thermal shock), from settling, or from water damage. A single cracked tile breaks the barrier.
- Corroded or damaged metal liners. Metal liners can corrode — especially cheaper materials in a coastal, salty, humid environment, or when exposed to the acidic condensate some appliances produce.
- Wrong size for the appliance. A flue that’s the wrong diameter for the stove, insert or furnace it serves won’t draft properly and can accelerate deposits and corrosion. Installing a new appliance often requires a correctly sized liner.
- No liner at all. Some very old chimneys were built unlined — not safe by modern understanding.
What relining involves
Relining installs a new, continuous liner inside the existing chimney. The most common solution is a stainless steel liner sized to the appliance and, where appropriate, insulated. Stainless holds up to heat, resists the corrosion that plagues cheaper metals in our climate, and — critically — is sized correctly for what it serves. Cast-in-place and tile options exist for specific situations, but a properly sized, well-installed stainless liner solves the majority of relining needs.
The right liner depends on the appliance and fuel — a wood stove, an open masonry fireplace, a gas insert and a furnace all have different requirements. Matching liner type, diameter and insulation to the appliance is the part that makes relining a real repair rather than just shoving a pipe up a hole.
Why the camera comes first
You can’t see a mid-flue crack from either end, so relining decisions are made from footage, not guesswork. We scan the flue to confirm what’s actually wrong, how far it runs, and whether it’s a true reline or a lesser repair. If someone recommends relining without showing you the inside of your flue, that’s a fair thing to question — and it’s exactly why we lead with the scan.
Repair vs. full reline
Not every liner issue is a full reline. A localized problem in an accessible spot can sometimes be repaired. But widespread cracking, a post-chimney-fire flue, corrosion along the length, or a size mismatch for a new appliance point to relining. We’ll base the recommendation on what the camera shows and what the appliance needs — and we’ll tell you plainly when a repair is a reasonable option versus when it’s a false economy on a flue that should be relined.
One note on scope and safety: relining ties into the appliance and venting system, and doing it correctly matters enormously. We treat it as the safety-critical work it is, not a quick add-on.
Questions people ask us
How do I know if my flue liner is cracked?
Usually you don’t without a camera — the damage is up inside the flue where you can’t see it from the firebox or the roof. Cracked liners are frequently found during a Level 2 inspection or after a chimney fire. If your chimney has had a fire, is very old, or has never been scanned, a camera look is the way to know.
Why stainless steel instead of a cheaper liner?
Because cheaper metal liners corrode, and in South Florida’s humid, salty air that happens faster. Stainless steel resists heat and corrosion and, when sized and insulated correctly for your appliance, is a long-term fix. A bargain liner that fails in a few years isn’t a bargain.
Do I need a new liner just because I’m adding a stove or insert?
Often, yes. A new appliance needs a flue of the correct diameter to draft and vent safely, and the existing flue is frequently the wrong size for it. A properly sized liner is part of installing an insert or stove correctly, not an optional upsell — it’s what makes the new appliance vent the way it’s designed to.