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National Building Code of Canada (NBC)

Also called: National Building Code · NBC 2020 · NBC 2025 · National Model Codes

Canada's model building code; once a province or territory adopts it, it sets minimum insulation, ventilation and safety rules for new homes and renovations.

What it means

The NBC is developed by the Canadian Board for Harmonized Construction Codes and published by the National Research Council, and it applies only once a province or territory adopts it, sometimes with changes. Part 9 covers houses and small buildings, and its energy rules (Section 9.36) are organized in performance tiers. The 2025 edition adds a passive radon stack for dwelling units and a new Part 10 on energy upgrades when existing buildings are altered.

Why it matters in an audit

Your province's version of the code sets the minimum insulation, ventilation and window levels for renovations and additions, and its climate zones are the ones quoted on many Canadian pages.

Typical numbers

Reference values with their sources. Your energy advisor’s report gives the figure for your own house.

What	Value	Source
Editions	NBC 2020 and NBC 2025 are both free to download from the National Research Council; which applies depends on your province or territory	nrc.canada.ca ↗
2025 changes affecting houses	Passive vertical radon stack in dwelling units, sealed air-barrier seams under slabs, updated energy tiers, and a new Part 10 for energy upgrades to existing buildings	cbhcc-cchcc.ca ↗

Sources

Related terms

NBC climate zone (Canada) Canada's building code climate zones, set by heating degree days: zone 4 (mildest) to zone 8 (coldest), with zone 7 split into 7A and 7B.
R-value How well a material resists heat flow; higher is better, and insulation is rated with it, such as R-20 for walls or R-50 for attics.
RSI (metric R-value) The metric version of R-value used in Canada; multiply RSI by 5.678 to get R, so RSI 8.8 is about R-50.
Radon A natural radioactive gas from uranium in soil and rock that can build up in homes; long-term exposure raises the risk of lung cancer.
CSA Group (Canadian Standards Association) Canada's main standards organization; building codes, rebates and product labels often point to its standards, such as F280 for heating system sizing.

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