NRCan recommends at least RSI 14.1 (R80) for roofs and ceilings in Zone 7a. The product amount still depends on the existing assembly and the exact Canadian label.
What the official table recommends
| Condition | Guidance | Scope |
|---|---|---|
| Roof / ceiling target | R80 (RSI 14.1) recommended minimum roof/ceiling value | NRCan Table 2-1; existing conditions and assembly limitations still control the project. |
This is a recommended minimum for the whole roof or ceiling. It is not an added layer or a bag count. Assess the existing assembly first, then match the required added R-value to a current Canadian product label.
What to check through the year
- Spring
Inspect for water, damage, and displaced insulation.
Condition must be known before adding depth.
- Summer
Complete safe inspection and accessible air sealing.
Unresolved penetrations should not be buried.
- Fall
Review access and product-label installation controls.
A high target still requires correct bag coverage and settled depth.
Before you plan the work
- Confirm the actual project zone using the cited official lookup or the authority that applies locally.
- Inspect existing material, moisture, air leakage, safe access, wiring, fixtures, and combustion equipment before top-up.
- Use the coverage chart on the current product label; do not transfer bag data between U.S. and Canadian products.
- Treat representative locations as classification examples, not local forecasts or code boundaries.
Sources and notes
Source links reviewed July 16, 2026. A review date is not the document's publication date.
- Natural Resources Canada: Keeping the Heat In — How your house worksCanada · government guide
Canadian guidance uses effective thermal resistance and climate-zone classifications.
- Natural Resources Canada: Keeping the Heat In — Roofs and atticsCanada · government guide
Follow product labels for bag count and settled depth; do not disturb suspected vermiculite.