Evaluation Rubric
The Scoring System, in Brief
Every building system on this site is scored on three axes: Drying Ability (Fast, Moderate, Poor, or None), Inspectability (Open, Partial, or Sealed), and VOC Tier (Zero-VOC, Near-Zero after cure, Documented, or Undisclosed). Those three axes produce one Verdict — Recommended, Conditional, or Not Recommended. The first two axes are the Two-Question Test (can it dry, can you inspect it); the third is the Chemical Question. The rubric is frozen: the same axes and definitions apply to every system, and the verdict follows the scores, never the other way around.
Why a Rubric, Not a Checklist
Building assemblies are systems, not feature lists. "Does it have mineral wool? Does it avoid OSB?" misses how the parts interact: an assembly with great insulation and poor flashing fails, while a wood assembly that dries quickly and stays inspectable can outperform an inorganic one that traps moisture. The rubric scores how the assembly behaves when water gets in and how its chemical load is handled — not its ingredient list.
How to Read the Score Badge
Every build-option page and material evaluation carries the same badge. The three axes are scored first; the verdict is read off them. Here is the badge for a recommended system:
The Two-Question Test
The first two axes come from the question every wall has to answer: when moisture gets in, can the wall dry, and can you find the problem before it spreads?
Axis 1 — Drying Ability
| Score | Meaning |
|---|---|
| Fast | Dries to both sides under normal conditions. |
| Moderate | Dries to one side only, or dries slowly. |
| Poor | Minimal drying path; stays wet long after wetting. |
| None | Vapor-closed with no drying path; trapped moisture stays trapped. |
Axis 2 — Inspectability
| Score | Meaning |
|---|---|
| Open | Framing, insulation, and sheathing can be examined without demolition. |
| Partial | Some components accessible, some sealed. |
| Sealed | Bonded to all surfaces; destructive removal required to inspect. |
The Chemical Question
Axis 3 — VOC Tier
The third axis carries equal weight to the first two. It scores the chemical disclosure of every wet-applied layer in the assembly.
| Score | Meaning |
|---|---|
| Zero-VOC | No measurable VOC emissions at any wet-applied layer. |
| Near-Zero after cure | Reaches near-zero emissions after a defined, disclosed cure period. |
| Documented | Emissions are disclosed and verifiable, but not near-zero. |
| Undisclosed | Emissions are not disclosed or cannot be verified in place. Fails the standard. |
How the Verdict Is Derived
The verdict is read from the three axis scores, applied the same way every time:
| Verdict | When it applies |
|---|---|
| Recommended | Strong drying ability and inspectability, with a Zero-VOC or Near-Zero VOC tier. No single axis is a serious failure. |
| Conditional | Acceptable performance is achievable, but only under stated conditions (specific detailing, climate, materials, or crew experience). The exact condition is named on the badge. |
| Not Recommended | One or more axes fail — typically None drying, Sealed inspectability, or an Undisclosed VOC tier. Scoped to the application stated in the verdict. |
The verdict follows the scores. A system is never scored backward from a conclusion we wanted to reach — if it were, this would be a rationalization, not a rubric. At least one recommended system is scored openly, including its limitations, to show the rubric drives the verdict and not the reverse.
Also Assessed (Not Scored on the Badge)
Two further factors inform our guidance but are not scored axes on the badge, because they describe practicality rather than indoor-air performance: contractor feasibility (whether qualified labor is available for the assembly) and documentation (whether material specifications are verified). These appear in the body of each evaluation, not on the badge.
The Rubric Is Frozen
These axes and definitions are fixed. They were set before the first scorecard was written, and they do not change to fit any individual system. A change to an axis definition is a formal revision that triggers re-scoring of every existing evaluation — logged in the corrections record. This is what lets a reader compare a spray-foam scorecard and a mineral-wool scorecard and trust they were measured the same way.
Evidence Standard
On every evaluation, each non-obvious technical or health claim is either backed by an inline source or explicitly labeled as Good Air Homes' evaluative judgment. There is no third category. See the spray foam scorecard for the rubric applied end to end, and the evidence policy for how sources are weighed.
Last reviewed: August 2026