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.
Ontario clearance questions, answered
| Question | Planning answer | What controls |
|---|---|---|
| How close can a stove be to a wall? | There is no single distance for every stove. Use the certified appliance label/manual; treat a missing or unreadable label as an uncertified-system question for professional review. | Listing instructions, applicable code, installation details, and the authority having jurisdiction. |
| Does tile make a wall non-combustible? | Tile or brick applied directly over wood-framed drywall does not remove the combustible construction behind it. | The complete wall assembly and any properly constructed clearance-reduction system. |
| Can heat shielding reduce clearance? | A qualifying ventilated shield may reduce a clearance, but material, spacing, ventilation, mounting, and permitted reduction must all be confirmed. | The applicable installation standard and appliance instructions. |
| What about a used or unknown stove? | Photograph every plate or marking and locate the manual before planning. Do not assume a second-hand appliance is certified or that a previous installation was acceptable. | Readable listing evidence, manufacturer instructions, condition, and the current installation. |
Floor protection has no universal default
Wall clearances do not determine the required hearth pad. Ember protection, thermal protection, loading-door position, appliance dimensions, and required extensions can differ by model and installation. Find the manufacturer-required front, rear, and side protection values, then use the hearth pad size calculator to total the overall footprint. The tool deliberately supplies no default clearances.
Chimney height is a separate geometry check
Stove-to-wall clearance does not determine chimney termination height. A preliminary chimney-height check compares the termination with the roof penetration and nearby roof or structure. Use the chimney height calculator to show that geometry, then defer to the appliance instructions, applicable code, and professional inspection.
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.
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