Rigid Stainless Liner

They're tiers of access, defined in NFPA 211. Level 1 covers readily accessible areas — the routine annual check when nothing has changed. Level 2 adds a camera scan of the flue interior plus attics and crawl spaces, and it's required at property sale, after a fire, or when the appliance or fuel changes. Level 3 involves removing components or finish materials to reach a suspected hidden hazard. Each tier has to be justified by the one below it.

NFPA 211 names the triggers: sale or transfer of the property, after a chimney fire or operating malfunction, after external events like storms or seismic activity, and whenever you change the fuel type or connect a new appliance. If any of those apply, a Level 1 isn't sufficient — the standard wants the flue interior scanned, not just eyeballed from the top and bottom.

A written report, standard turnaround 48 hours. It lists every checkpoint with a pass or fail verdict, a photo behind each finding, the relevant code or standard reference, and — when something fails — what correcting it involves. It's a document you can forward to an insurer, a buyer, or another contractor for a competing bid. Nothing we say on-site counts until it's in the report.

The honest answer is: when measurement says so. NFPA 211 requires annual inspection, but sweeping is triggered by creosote depth — 1/8 inch is the threshold. A fireplace burning most nights all season usually hits that in about a year. Occasional weekend fires might take two or three. We measure at each inspection and only recommend a sweep the measurement supports.

General home inspectors do visual checks from the ground and the firebox — their own standards of practice put chimney flue interiors outside scope. The failures that cost real money, like gapped flue tiles and hidden cracking, only show on a camera scan. That's why NFPA 211 specifies a Level 2 at property transfer. Plenty of chimneys pass; the point is knowing before you close, not after.