Flexible Chimney Liner Installation

This is a material decision, not a separate service: when a flue needs a liner, should it be the flexible corrugated stainless tube or a rigid one? Flexible is the answer precisely when geometry defeats rigid pipe — an offset or 'dogleg' in the stack, an elbow at the smoke chamber, an out-of-round or shouldered clay tile, or a tight throat a stiff length can't be fed through. The corrugation lets the liner bend through the turns and compress through the pinch points while still sealing as one continuous channel. Where relining is the broader decision to replace a failed liner and may end in flexible, rigid, or cast-in-place, this is specifically the flexible option, chosen on geometry and appliance, whether the flue is being relined or lined for the first time.

Choosing flexible is a measurement before it's a purchase. The flue is camera-scoped and every offset, elbow, and dimensional pinch mapped, then the call is whether flexible is required (rigid won't pass) or merely preferred. Where rigid would pass a straight, accessible flue, we say so — rigid has smoother walls and marginally better draft, so flexible is never the default sell. A tight throat gets an oval-profile flexible liner of equal cross-sectional area so it passes where a round one won't. Alloy still tracks the fuel — 316Ti stainless for wood, oil, coal, or high-sulfur fuels, 304 where the fuel allows — because a flexible liner in the wrong alloy corrodes exactly as fast as any other.

Flexible is also the natural match for appliance venting, which is much of why the type exists. Dropping a liner from a gas or wood fireplace insert to the appliance collar nearly always means negotiating the offset between the flue and the insert's outlet, and flexible makes that positive, full-length connection where rigid would bind — never a non-connected 'slammer.' Venting a stove or high-efficiency appliance through an existing masonry chimney is the same geometry problem, and the flexible tube solves it. Because corrugation slightly slows draft and runs cooler, a liner-insulation wrap goes on for solid-fuel and many appliance installs — it holds flue temperature up for draft, keeps creosote down, and maintains clearance to combustibles where the run passes near framing.

Installation is geometry-aware top to bottom: the liner is fed from above, eased through each offset rather than forced, insulated or pour-mixed as required, and locked to positive top-plate and appliance-collar connectors so the corrugated run is gas-tight end to end. Then it's proved — a smoke or draft check confirms the sealed path, and the UL-1777 listing is documented for your records and any warranty, which on flexible liners is typically conditional on annual sweeping. Unlike flue installation, which often builds a brand-new straight flue where smooth clay or rigid is the better first-time choice, flexible is the retrofit answer for an existing crooked flue rigid can't follow. The same scoping, alloy-matching, and insulation discipline governs every flexible-liner install across our national network.