Chimney Relining in Rochester

Before the mid-20th century, clay tile liners weren’t universal, and plenty of city-of-Rochester and inner-ring-suburb chimneys were built with bare brick as the only barrier. Clay tile liners themselves have a known failure mode: the same freeze-thaw cycling that spalls exterior brick also cracks the mortar joints between tile sections from the inside, especially in chimneys that saw a chimney fire at some point (even a minor one most homeowners never noticed). A Level 2 video inspection is what actually catches this — cracked tile joints aren’t visible from a Level 1 walk-around.

Appliance changes trigger relining too. Swapping an oil furnace for a high-efficiency gas unit, or adding a wood insert to an open fireplace, changes the flue gas temperature and moisture profile enough that code (and most manufacturers’ install instructions) require a liner sized for the new appliance. An oversized, unlined flue built for a big open fireplace doesn’t draft correctly for a smaller gas appliance — that’s the mechanism behind a lot of the "my furnace guy said I need a liner" calls we get.

Stainless steel liners are the standard for wood-burning and most gas retrofits — flexible or rigid sections sized to the appliance, insulated where code requires it (uninsulated stainless against old masonry is a common inspection fail). Cast-in-place liners pump a lightweight cementitious material around a rubber form, which both lines the flue and adds structural reinforcement to a deteriorating masonry chimney — the right call when the masonry itself is marginal, not just the liner. HeatShield is a resurfacing product for chimneys with moderate tile-joint cracking that don’t need a full structural fix — cheaper than cast-in-place, not appropriate for chimneys with real structural movement.

Most residential relining jobs are a single day: flue measurement and video-verified sizing, liner installation from the top down, insulation wrap (for stainless), connection to the appliance, and a post-install Level 2 scan to confirm the liner runs clean top to bottom with no gaps at the connections. Cast-in-place jobs run longer — typically two days with a cure period. Either way, you should get the post-install video, not just a verbal "it’s good" — that’s the documentation an insurance carrier or a future buyer’s inspector will ask for.