Effective R-values, against the table that governs.
Four of the eleven Ontario rules here read the drawing, and they are the assemblies: walls, attic, foundation and slab edge, against the SB-12 table for Climate Zone 6. The other seven are the standing checklist an energy report answers.
What the engine reads off the drawing
Every reader runs on every file, whichever trades the audit is scoped to. Choosing this trade decides which rules get reported. The drawing is read either way.
Assemblies, from the wall types
Where a set schedules its assemblies, the effective RSI is compared against the SB-12 minimum for the zone: RSI 4.03 above grade, RSI 10.14 at the attic.
Foundation and slab edge
Foundation walls and slab-on-grade perimeter insulation checked against their own minimums, which are the two most often left at the last project’s number.
What the drawing states, not what it implies
A nominal batt value is not an effective R-value. Where a set gives only the nominal, the finding says so instead of converting it with an assumed framing factor.
11 Ontario rules, and which of them read the drawing
Answered from the drawing means the check reaches a pass or a fail from what was extracted. Checklist means the rule is printed with its clause for a person to confirm. Both are useful on a permit set, and only the first is a finding.
| Clause | What it requires | How it is answered |
|---|---|---|
| OBC 2025 SB-12 Table 12.2.1.5 (CZ6) | Above-grade wall effective thermal resistance (CZ6): RSI 4.03 minimum | From the drawing |
| OBC 2025 SB-12 Table 12.2.1.5 (CZ6) | Attic/ceiling minimum RSI-10.14 (R-57.6) for Climate Zone 6 | From the drawing |
| OBC 2025 SB-12 Table 12.2.1.5 (CZ6) | Foundation wall minimum RSI-3.85 (R-21.8) for Climate Zone 6 | From the drawing |
| OBC 2025 SB-12 Table 12.2.1.5 (CZ6) | Slab-on-grade perimeter insulation minimum RSI-1.76 (R-10) for Climate Zone 6 | From the drawing |
| OBC 2025 Article 9.25.4.1 | Vapour barrier required on warm side of insulation in all exterior walls and ceilings | Checklist |
| OBC 2025 Article 9.27 / OFC General | Combustible cladding — OBC Part 9 buildings have no height restriction on combustible cladding | Checklist |
| TGS Version 4 — TEF 1.1 | Building airtightness ≤ 2.5 ACH@50Pa — blower door test required | Checklist |
| TGS Version 4 — TEF 1.2 | Energy performance minimum 15% better than OBC SB-10 reference building | Checklist |
| TGS Version 4 — TEF 1.3 | EnerGuide energy label required at occupancy | Checklist |
| TGS Version 4 — RE 1.1 | Solar-ready roof — structural and electrical provisions for future PV installation | Checklist |
| TGS Version 4 — RE 1.2 | Battery storage ready — space and electrical rough-in for home energy storage system | Checklist |
Counts and clauses are exported from the rule packs themselves, by the same function the trade picker inside Blueprint Auditor calls.
What the other packs carry
Ontario is the deepest pack because it is where the rules were written first. Each column shows what that pack holds today, and a zero is a zero rather than a blank.
| Pack | Rules in this trade | Answered from the drawing |
|---|---|---|
| Ontario | 11 | 4 |
| British Columbia | 0 | 0 |
| National Building Code (Canada) | 0 | 0 |
| California | 0 | 0 |
| Florida | 1 | 0 |
| New York City | 0 | 0 |
| IRC (model code) | 0 | 0 |
| England | 0 | 0 |
Said before you pay for it
- This is not an energy model. SB-12 has a performance path, and a building that fails the prescriptive table can comply through it, which a drawing cannot show.
- Climate Zone 6 is what the Ontario pack carries. A Zone 7 project needs the Zone 7 table, and using the wrong one is worse than checking nothing.
- Air-tightness, ventilation rates and mechanical efficiencies are reported as checklist items. They are commissioning facts, not drawing facts.
- Nothing here is a permit approval. It is the first pass an experienced reviewer makes, done in minutes and cited to the clause.
Bring the hardest set you have.
A real set off a live job. The audit runs in minutes and every finding carries the clause and the sheet, so you can check the ones you disagree with.