Is there a difference in code requirements between heated and unheated spaces in NB? | Insulation IQ?

Yes, there is a meaningful and intentional distinction in the New Brunswick Building Code between heated and unheated spaces, and understanding that distinction is essential for any renovation or new construction project in the province. The code logic is straightforward: insulation is required at the thermal boundary — the point where conditioned living space meets unconditioned or exterior space. Where no heating occurs, different thresholds apply, and in some cases no insulation requirement exists at all within that unheated area itself.

For a typical New Brunswick home in Climate Zone 6, the thermal boundary is what drives all the R-value requirements. A heated basement, for instance, is considered conditioned space, so the insulation requirements shift from the basement floor to the above-grade basement walls — the code requires those walls to achieve RSI 1.96 (approximately R-11) for the portion below grade, though the Part 9 residential prescriptive path and energy code alignment push effective wall assembly values considerably higher in practice. An unheated basement or crawlspace, by contrast, moves the thermal boundary up to the floor assembly above it. In that scenario, the floor over the unheated space must meet a minimum of RSI 5.02 (R-28.6) under the current NB prescriptive requirements for Climate Zone 6.

This distinction matters enormously in older Moncton, Fredericton, and Saint John homes where a garage might be attached but unheated, or where a crawlspace is vented and unconditioned. If you insulate the wrong plane — say, the crawlspace walls instead of the floor above it — you may end up with inadequate thermal performance, moisture issues, and a code deficiency. Inspectors will look at where the thermal boundary is and whether the insulation at that boundary meets the minimum RSI.

The same logic applies to attached unheated garages. The shared wall between a heated living space and an unheated garage is a thermal boundary wall and must be insulated to meet the wall assembly R-value requirements (effectively R-22 to R-24 in a wood-frame assembly). The garage floor itself, being unheated and not adjacent to conditioned space from below, has no thermal insulation requirement under the code — though a vapour barrier on the slab may still be required depending on the design.

Attic spaces present an interesting case. A vented unconditioned attic is not a heated space, so the code doesn't require you to insulate the attic walls or roof deck. Instead, the thermal boundary sits at the attic floor (the ceiling of the floor below), and that's where the R-60 or higher requirement for Climate Zone 6 attic insulation applies. If you convert that attic to a conditioned living space or create an unvented conditioned attic assembly, the thermal boundary moves to the roof deck, triggering different requirements entirely.

One nuance worth highlighting: Part 11 of the NB Building Code covers existing buildings and energy efficiency retrofits, and it acknowledges that full prescriptive compliance isn't always physically achievable in older structures. However, any new insulation work still needs to meet minimum thermal resistance levels at the applicable boundary. Permit requirements and inspections also differ — a full renovation in a heated living area will almost always require a permit and insulation inspection, while simply adding batt insulation in an unheated utility space may not.

For homeowners planning upgrades to qualify for NB Power's Home Energy Savings Program or the Canada Greener Homes Grant, understanding heated vs. unheated space distinctions is also financially important. Rebates are typically calculated based on improvements to the thermal boundary — insulating an unheated space itself won't trigger a rebate unless it changes the thermal performance of the boundary separating conditioned from unconditioned area.

If you're unsure where your thermal boundary sits or whether your planned insulation work meets the code for your specific home configuration, the professionals listed on New Brunswick Insulation can assess your project and ensure you're insulating the right plane at the right R-value.

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