How often should a chimney be inspected in Canada?

The National Fire Protection Association (NFPA 211) recommends annual chimney inspections for any chimney in use. In Canada, this is especially important for wood-burning fireplaces and stoves, which accumulate creosote — a highly flammable byproduct of incomplete combustion. Oil-fired appliance flues should be inspected annually by the appliance service technician. If you've purchased an older home with a chimney that hasn't been inspected in years, have a Level 2 WETT inspection done before first use.

What is WETT certification and why does it matter?

WETT (Wood Energy Technology Transfer) is the Canadian standard for inspecting, installing, and certifying wood-burning systems including fireplaces, wood stoves, and their chimneys. A WETT inspection is performed by a WETT-certified technician and is often required by home insurers in Canada before coverage will be extended for a home with a wood-burning appliance. Level 1 WETT inspections are visual; Level 2 involves access to concealed areas and is recommended at the time of purchase of any older home.

Can I install a woodstove in an old chimney?

Not without a liner assessment. Pre-1980 masonry chimneys were often built with unlined flues or deteriorated clay tile liners that are not suitable for modern high-efficiency woodstoves or pellet stoves. A stainless steel flexible liner must be installed to match the stove's flue outlet size and ensure proper draft. Installing a stove without an appropriate liner is a fire hazard and will violate building codes in every Canadian province. A WETT inspection will identify what liner work is required.

Does home insurance in Canada require a chimney inspection?

Some Canadian insurers may require a WETT inspection before extending coverage on homes with wood-burning appliances. Even where not mandated, failure to disclose a known chimney defect and then experiencing a chimney fire could affect a claim. As part of your purchase process, consider obtaining a WETT Level 2 inspection and sharing the results with your insurer, and confirm requirements and any potential discounts in writing with your insurer.

What causes a chimney fire and how would I know if I've had one?

Chimney fires are caused by ignition of creosote deposits — a tar-like residue that builds up inside flues when wood is burned at low temperatures (green wood, smoldering fires). Chimney fires can burn very hot and may cause clay tile liners to crack, mortar joints to fail, and in severe cases, spread to combustible framing. Possible signs of a past chimney fire include honeycomb or puffy creosote inside the flue, cracked or collapsed clay tiles, a warped damper, exterior brickwork cracks, or a strong smoke smell in the attic. Do not disturb the appliance or flue and do not use a fireplace or stove after a suspected chimney fire — have it assessed by a WETT-certified technician and get written confirmation it is safe to use before resuming.

Specialist confirmation

Chimney & Flue Failure

Fire and carbon monoxide risks from deteriorated chimneys in pre-1980 Canadian homes

Quick Overview

Most pre-1980 Canadian homes were heated by oil or wood, and their chimneys used clay tile liners or were completely unlined. After decades of use, these flues develop cracks, spalling, and creosote buildup that create serious fire and carbon monoxide risks.

Common in:Pre-1980 homes

Fire & CO risk:Yes

WETT inspection:Required

How to Identify Chimney Problems

• Spalling or missing mortar between exterior bricks
• White efflorescence (mineral staining) on exterior chimney brickwork
• Cracked clay tile liner visible with a flashlight from above
• Rust staining on ceilings or walls near chimney
• Draft problems — smoke entering the room instead of exhausting
• Woodstove insert installed without a proper flue liner
• Chimney crown (the concrete cap) cracked or deteriorated

Major Risks

• Chimney fire from creosote ignition (burns very hot, risking flue and structural damage)
• Carbon monoxide poisoning from cracked or blocked flue liner
• House fire from gap between deteriorated liner and combustible framing
• CO backdraft from negative pressure in tight modern homes
• Structural collapse of deteriorated unlined masonry chimney
• Water infiltration through cracked crown or missing cap

Cost Considerations

Costs for a chimney sweep and inspection, a WETT Level 2 inspection, liner repair, stainless steel liner installation, or a full chimney rebuild vary by scope, region and contractor. Ask for itemized written quotes from licensed, WETT-certified professionals.

Professional Recommendations

Immediate Actions:

• Do not use a fireplace or woodstove in an uninspected older home
• Install CO detectors on every floor — especially near bedrooms
• Book a WETT Level 2 inspection before the first use of any season
• Have all flues swept before oil/gas furnace service each fall

Long-term Solutions:

• Install a properly sized stainless steel liner for any new appliance
• Repair chimney crown and flash seams to prevent water intrusion
• Annual sweeping is strongly recommended for wood-burning appliances
• Obtain WETT certificate and share with home insurer

In pre-1980 homes, chimneys often served multiple appliances (furnace, water heater, and fireplace) through a single flue — a configuration that creates dangerous backdraft conditions in modern airtight renovations. A WETT-certified technician can assess whether your multi-appliance flue configuration is still safe after any renovations or appliance changes. See also our Lead Paint Guide for other hazards common to pre-1980 Canadian homes.

Common questions

Frequently Asked Questions About Old Canadian Houses

Common questions from buyers and owners of older Canadian homes, answered with era context and pointers to the professionals who can confirm anything on a specific property.

Have a question not answered here? Browse our full inspection guide or explore all resources.

Chimney & Flue Failure

Quick Overview

How to Identify Chimney Problems

Major Risks

Cost Considerations

Professional Recommendations

Immediate Actions:

Long-term Solutions:

Frequently Asked Questions About Old Canadian Houses

MaintenanceHow often should a chimney be inspected in Canada?

StandardsWhat is WETT certification and why does it matter?

WoodstovesCan I install a woodstove in an old chimney?

InsuranceDoes home insurance in Canada require a chimney inspection?

Fire SafetyWhat causes a chimney fire and how would I know if I've had one?