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Canada R Value Requirements

How codes work in Canada

The National Building Code of Canada and the National Energy Code are model codes published by the National Research Council. They have no legal force until a province or territory adopts them, sometimes with changes. Some provinces, such as Ontario, Quebec and British Columbia, publish their own codes based on the national model. Some municipalities, like those with step codes, add higher performance tiers. Because of this, the exact R-value (or RSI) your attic, walls or basement must meet depends on where you live, the climate zone assigned to your area, and whether the work is new construction, an addition or a renovation.

Where to look

• Natural Resources Canada (NRCan): homeowner guidance on energy efficiency and insulation, including the well-known *Keeping the Heat In* guide, linked from NRCan's energy efficiency for homes section.
• Your provincial or territorial building code: the legal requirement for permitted work.
• Your municipal building department: tells you which code edition applies and whether a permit is needed.
• A registered energy advisor: can assess your home and recommend levels.

We do not list specific required values here because they vary by jurisdiction and edition and change over time; listing a number without your location could mislead you.

RSI and R

Canadian codes usually state thermal resistance in RSI (metric), sometimes with the imperial R equivalent. To convert: R ≈ RSI × 5.678, and RSI ≈ R ÷ 5.678. For example, RSI 8.67 is about R49, and RSI 10.43 is about R59. Our calculators use imperial R because most product labels in Canada also show it.

Climate zones in Canada

Canadian codes divide the country into zones by heating degree days (HDD). Colder zones, with more HDD, generally require more insulation. Your municipality's HDD value is in the code's climatic data tables. Our insulation savings calculator also uses HDD.

Renovations vs new homes

Codes mainly apply to new construction and to work that needs a permit. Adding attic insulation to an existing home may or may not need a permit; ask your municipality. Even when no permit is needed, using code levels for new homes as a target is a reasonable benchmark, and NRCan's guidance can help you choose.

Incentives

Federal, provincial and utility programs have offered help with insulation upgrades, often requiring a pre- and post-retrofit energy evaluation by a registered advisor. Programs open, change and close. We do not quote amounts; see insulation rebates for how to find current official programs.

Vermiculite in Canadian homes

Health Canada advises that vermiculite insulation, much of it sold as Zonolite and made from Libby, Montana ore before 1990, may contain amphibole asbestos. It says not to disturb it, not to use the attic for storage, to keep children out, and to hire trained professionals. See Health Canada's asbestos guidance.

Worked example

Figures below are illustrative examples (2026-10-29), not quotes or guarantees.

Assumptions: your municipality tells you the target for your attic is RSI 8.67 (an example value, not your code). That is 8.67 × 5.678 ≈ R49. You have 5 in of old fiberglass batts at an assumed R3.2/in (R16). R to add ≈ 33; with loose-fill at an assumed R2.5/in that is about 13.2 in.

Using NRCan guidance

NRCan's homeowner materials explain how heat moves through a house, how to find air leaks, which materials suit which spaces, and how to plan a retrofit in a sensible order. They are a good starting point before speaking with a contractor or energy advisor, because they help you ask the right questions about air sealing, vapour control and ventilation that suit Canadian winters.

Vapour control in cold climates

Canadian codes in colder regions generally require a vapour barrier or retarder on the warm side of the insulation in walls and ceilings, though details differ. In attics, adding insulation over an existing ceiling usually does not need a new vapour barrier; adding one on top of old insulation can trap moisture. Air sealing at the ceiling plane is the more important step. Ask your building department for local requirements.

Ice dams and snow load

Many Canadian homes face ice dams. Air sealing, insulation to a good level, and continuous soffit-to-ridge ventilation all help. Baffles keep vents open; see attic ventilation baffles.

Older homes

Older Canadian homes may have little attic insulation, knob-and-tube wiring, balloon framing or vermiculite. Each changes the plan. Have wiring checked by an electrician and treat vermiculite as Health Canada advises before adding insulation.

Converting RSI and R

Canadian materials often list RSI. Multiply RSI by 5.678 to get R, or divide R by 5.678 for RSI. For example, RSI 8.8 is about R-50, and R-60 is about RSI 10.6. Rounded numbers on labels may differ slightly. Use our R-value stack calculator to add layers.

Before you start

Confirm local code with your municipality, check for hazards, plan air sealing, and look up current federal, provincial and utility programs on official sites before booking work, since some require an assessment first.

Bottom line

Use provincial code and NRCan guidance as your base, convert RSI carefully, and air seal before you insulate.

FAQ

What R-value does Ontario require?

It depends on the code edition and compliance path; ask your building department or check the Ontario Building Code.

Is NRCan's guidance a legal requirement?

No; it is guidance. Codes are the legal requirement.

Do I need an energy advisor?

Not to insulate, but many incentive programs require one.

Can I use the ENERGY STAR table?

It is U.S. guidance; use it only as a general reference in Canada.

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