Ontario Wood Stove Clearance Calculator
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Enter the positive clearance printed on the appliance listing label.
Minimum Required Clearance
Floor protection and connector-pipe clearances are separate requirements. Follow the appliance label, installation manual, and the requirements confirmed by your local authority or WETT-certified inspector.
Certified vs. Uncertified Stoves: The 48-Inch Rule
When determining how close you can safely place your wood stove to a combustible wall, the very first step is checking for a listing label. If your stove has a ULC or CSA listing tag attached to the back, it is "Certified." You must follow the exact side and rear clearances printed on that label. If you are still choosing an appliance, start with the Wood Stove BTU Sizing Calculator so you know the heat output range before planning clearances.
If the stove has no readable listing label, it must generally be evaluated as an uncertified appliance. A common CSA B365 baseline for an uncertified radiant stove is 48 inches (1200 mm) from combustible construction before an approved clearance-reduction system is considered. Appliance type, connector pipe, shielding details, and local requirements can change the final installation decision.
How to Safely Reduce Your Wall Clearance
You can safely reduce the required clearance distance by installing a proper heat shield, but it must be done strictly according to the CSA B365 standard.
The most important feature of any clearance shield is the air space. The shield must be spaced out from the wall by at least 7/8 of an inch (typically 1 inch) using non-combustible spacers. There must also be a 1-inch to 3-inch gap at the bottom and top of the shield to allow air to flow vertically. This convection flow is what actually keeps your drywall safe.
If you follow these rules, you can reduce your required clearance by:
- 67% using a minimum 29-gauge sheet metal shield.
- 50% using ceramic tile or brick veneer.
Don't Forget Your Floor Pad Protection
Wall clearances are only half the battle. Your non-combustible floor pad (or hearth extension) must also meet strict size requirements to protect your home from falling embers. In Canada, your floor pad must extend at least 18 inches (450 mm) in front of the loading door, and 8 inches (200 mm) beyond the sides and rear of the appliance. If you are installing a heavy uncertified stove, the floor pad rules become even more complicated depending on the height of the stove legs. Before you light your first fire, ensure your math is correct by booking a certified professional.
Frequently Asked Questions
Can I just glue brick or tile directly to my drywall to protect it?
No. A non-combustible wall must be made of non-combustible materials throughout the entire wall assembly (like a solid concrete wall). Gluing brick or tile directly to wood-framed drywall does not count as a heat shield because there is no air gap. Without that 1-inch air gap, the heat conducts right through the brick and can easily ignite the drywall behind it.
My insurance company is asking for a WETT Certificate for my uncertified stove. What do I do?
First, know that a "WETT Certificate" does not actually exist-your insurer is simply asking for a formal Inspection Report. Second, be aware that while some insurers will cover uncertified stoves if they perfectly meet the 48-inch CSA B365 clearances, many modern insurance companies will flat-out refuse to insure uncertified wood stoves.
Does my single-wall flue pipe need clearances too?
Yes. Uncertified single-wall flue pipe generally requires an 18-inch clearance from combustible walls and ceilings. Just like the stove, this distance can be reduced by 50% if you install a proper sheet metal shield with an air gap.