TryBuildCalc

R-Value Calculator Verification Checklist

Essential Checklist+

Complete these critical checks before approving the work or proceeding to the next construction stage.

✓11 Inspection Points
✓5 Verification Categories
✓Assembly Definition+
  • Assembly type (wall, ceiling/attic, or floor) matches the actual component being evaluated.
  • Every layer that is genuinely present in the real assembly was entered — exterior finish, sheathing, continuous insulation, interior finish — not just the cavity insulation.
  • Framing material and spacing (and, for wood, depth) match the actual studs or joists on site, not an assumed default.
  • For a wall with both cavity and continuous insulation, both were entered as separate layers rather than combined into one lump R-value — the framing correction and code comparison both depend on knowing the two amounts apart.
✓Material & Framing Accuracy+
  • For a SIP, ICF, or other non-stud wall, "None (SIP/ICF - no studs)" framing was selected and the manufacturer's own tested whole-wall R-value was used for any real comparison, not this calculator's generic nominal R-value entry alone.
✓Interpreting the Result+
  • The Effective (whole-assembly) R-value — not the Nominal R-value — was used for any real performance comparison or energy-model input, since the nominal number overstates real performance.
  • Steel-framed and SIP/ICF wall results were not checked against this calculator's IECC comparison — that comparison is intentionally skipped for those framing types since the code requires a different table for each.
✓Code & Compliance Verification+
  • The correct, currently-adopted energy code edition and any local amendments were confirmed with the local building department — this calculator uses the 2021 IECC base table (Table R402.1.3).
  • The selected climate zone matches the project's actual county/location, not an assumption.
✓Installation Quality (Not Modeled by R-Value Alone)+
  • Insulation is installed at full, uncompressed thickness across the full cavity depth — a compressed batt loses real R-value this calculator cannot detect from an R-value input alone.
  • Insulation fully fills the cavity with no gaps, voids, or compressed corners around wiring, boxes, or blocking.
Full QC Checklist+

Verify assembly definition, result interpretation, code basis, and installation quality before relying on an R-value result.

✓21 Inspection Points
✓5 Verification Categories
✓Assembly Definition+
  • Assembly type (wall, ceiling/attic, or floor) matches the actual component being evaluated.
  • Every layer that is genuinely present in the real assembly was entered — exterior finish, sheathing, continuous insulation, interior finish — not just the cavity insulation.
  • Framing material and spacing (and, for wood, depth) match the actual studs or joists on site, not an assumed default.
  • Cavity/topping insulation type and R-value match the real, specific product being installed or assessed, not a generic guess.
  • For a wall with both cavity and continuous insulation, both were entered as separate layers rather than combined into one lump R-value — the framing correction and code comparison both depend on knowing the two amounts apart.
✓Material & Framing Accuracy+
  • Steel-framed walls: stud depth was selected to match the real product even though it does not change this calculator's effective R-value result directly — depth still affects which real insulation products physically fit the cavity.
  • Advanced (OVE) framing was only selected if the wall is actually built to that specification (single top plate, two-stud corners, no extra cripples under headers) — not assumed by default.
  • Fixed material R-values (siding, sheathing, drywall, flooring) were checked against the actual installed thickness, not just the nearest catalog option.
  • For a SIP, ICF, or other non-stud wall, "None (SIP/ICF - no studs)" framing was selected and the manufacturer's own tested whole-wall R-value was used for any real comparison, not this calculator's generic nominal R-value entry alone.
✓Interpreting the Result+
  • The Effective (whole-assembly) R-value — not the Nominal R-value — was used for any real performance comparison or energy-model input, since the nominal number overstates real performance.
  • The U-factor was checked against any spec or code table that specifically calls for U-factor rather than R-value.
  • Steel-framed and SIP/ICF wall results were not checked against this calculator's IECC comparison — that comparison is intentionally skipped for those framing types since the code requires a different table for each.
✓Code & Compliance Verification+
  • The correct, currently-adopted energy code edition and any local amendments were confirmed with the local building department — this calculator uses the 2021 IECC base table (Table R402.1.3).
  • The selected climate zone matches the project's actual county/location, not an assumption.
  • The IECC comparison was understood as the R-VALUE ALTERNATIVE path (Table R402.1.3), not the primary U-factor path (Table R402.1.2) — a wall can legitimately pass one path and fail the other.
  • Every listed compliance path for the zone (e.g. a cavity-only number, or a specific cavity-plus-continuous combination) was checked — meeting any ONE path is sufficient, not all of them.
  • For a steel-framed wall intended for a code submittal, the result was cross-checked against the certified ASHRAE 90.1/NAIMA correction-factor table or a licensed energy model rather than relying on this calculator's approximation alone.
✓Installation Quality (Not Modeled by R-Value Alone)+
  • Insulation is installed at full, uncompressed thickness across the full cavity depth — a compressed batt loses real R-value this calculator cannot detect from an R-value input alone.
  • Insulation fully fills the cavity with no gaps, voids, or compressed corners around wiring, boxes, or blocking.
  • Air sealing (top and bottom plates, penetrations, rim joists) is addressed separately — air leakage reduces real-world performance independently of R-value and is not modeled by this calculator.
  • Any required vapor retarder/barrier placement and condensation-control detailing follows the local code and climate zone, not just the R-value target.
Inspection Notes+
Use the latest approved drawings, specifications, and site measurements.
Complete all critical checks before proceeding to the next work stage.
Record deviations and confirm rectification where required.

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R-Value Calculator CalculatorOpen the related calculator and verify the current project inputs.

FAQ

Use it after collecting the project inputs and again before approving or closing the relevant work stage.
No. It supports verification but does not replace approved drawings, specifications, codes, manufacturer requirements, or professional inspection.