Annual Chimney Inspection: What to Check and When
Chimney inspection in Canada follows a structured framework based on the NFPA 211 standard and, more specifically, the Wood Energy Technology Transfer (WETT) inspection protocols required by most provincial insurance carriers. The frequency and depth of each inspection depends on how often the appliance is used, the fuel type burned, and whether any changes have been made to the structure.
Canadian heating seasons are long — generally running from late September through April — and wood-burning appliances often operate daily for five to seven months. This intensity of use accelerates creosote accumulation and increases wear on liner components compared to appliances used only occasionally.
The Three Levels of Chimney Inspection
WETT-certified technicians and chimney sweeps in Canada reference a three-tier inspection framework. Each level covers more ground than the previous one and is appropriate for different circumstances.
Level 1 Inspection
A Level 1 inspection is the standard annual check for a chimney that has been in continuous use with no significant changes to the appliance or venting system. The technician examines accessible portions of the interior and exterior without using specialized tools or removing components.
Level 1 typically includes
- Visual inspection of the firebox, smoke chamber, and damper operation
- Checking the flue opening for obstructions (bird nests, debris)
- Assessing the chimney cap, crown, and exterior mortar joints
- Estimating creosote buildup and recommending sweeping if necessary
- Confirming proper clearances from combustible framing
Level 2 Inspection
A Level 2 inspection is required when a property changes ownership, when a different appliance is connected to the same flue, or after a chimney fire, seismic event, or any structural change to the home. This level includes a video scan of the full flue interior using a camera system, which reveals cracks, gaps in liner sections, and deteriorated mortar that are not visible from above or below.
In many Canadian provinces, lenders and insurers require a Level 2 inspection report as a condition of mortgage approval for homes with solid-fuel-burning systems. The Ontario Fire Code, for instance, does not mandate inspection intervals directly, but insurance carriers routinely enforce them through policy conditions.
Level 3 Inspection
A Level 3 inspection involves partial or complete removal of structure to access hidden areas. This is reserved for situations where Levels 1 and 2 have identified serious concerns that cannot be adequately assessed without demolition. It is uncommon in routine maintenance contexts.
Creosote: Stages and Assessment
Creosote is a byproduct of incomplete combustion. It forms when smoke contacts cooler surfaces in the flue and condenses. There are three recognized stages:
- Stage 1 (dusty/flaky): Light grey or black flakes that brush away easily. This stage is manageable with standard sweeping tools.
- Stage 2 (crunchy/tar-like): Hardened deposits that require rotary cleaning tools. More common when wet wood or slow-burning fires are the norm.
- Stage 3 (glazed): A smooth, shiny coating that resists mechanical removal. Chemical treatment is typically required before mechanical cleaning can proceed.
WETT-certified technicians use a degree-of-buildup scale when recording inspection findings. A deposit depth of 3mm or more in any flue segment generally triggers a sweep recommendation before continued use.
WETT Standards in Canada
The Wood Energy Technology Transfer program, administered through HRAI (Heating, Refrigeration and Air Conditioning Institute of Canada), provides the national framework for technician certification and inspection reporting. A WETT inspection report documents the appliance make and model, installation clearances, chimney connector condition, liner integrity, and any deficiencies identified.
A WETT inspection is not a pass/fail test — it is a documentation of existing conditions and any deviations from CSA B365 or manufacturer specifications at the time of inspection.
Homeowners should retain WETT inspection reports for insurance purposes. Many insurers in Ontario, British Columbia, and Alberta will not renew or transfer policies covering homes with wood-burning appliances without a WETT report on file dated within the past few years.
When to Schedule an Inspection
The end of the heating season — typically April through June in most Canadian provinces — is the preferred window. Scheduling in spring allows any structural repairs or relining work to be completed during summer before the next heating season begins. Technicians are generally easier to book during this period than in September and October, when demand surges.
For appliances used daily throughout winter, an annual Level 1 inspection with sweeping is a reasonable baseline. Appliances used heavily or burning wood with high moisture content may require sweeping mid-season as well.