Materials Library
How to Use the Materials Library
Materials are judged here mainly on their chemical load — how much they off-gas and how fully those emissions are disclosed — with moisture and mold behavior as the second factor. This is different from how we score whole wall assemblies, which turns on drying and inspectability. The pages below take you from "what to avoid" through "what to use instead" to a ranked, category-by-category shortlist.
How We Evaluate a Material
Two questions decide a material's place: does it emit volatile compounds, and is that emission disclosed and verifiable? A product that is low-emitting but undocumented is treated with caution; a product that discloses a defined cure period and settles to near-zero can still pass. Where a material sits in a wet part of the assembly, we also ask whether it feeds mold. The full definitions live in the glossary, and the assembly-level logic is in the scoring rubric.
Good / Better / Best — at a Glance
For everyday choices, the Good/Better/Best tables rank lower-risk options in each category — insulation, sheathing, interior surfaces, sealants, paint, flooring, roofing. "Best" is the lowest-risk, best-disclosed pick; "Good" is an acceptable baseline. Anything below "Good" is on the avoid list.
The Material Guides
Good / Better / Best Tables
Ranked picks by category, VOC and disclosure first. The fastest way to specify a healthier material.
Safer Alternatives
"Instead of this, use that" — the reasoning behind each substitution, in plain language.
What to Avoid
The common materials that fail the standard, and exactly why they create air-quality or moisture problems.
Mineral Wool vs Sheep Wool
The insulation matchup in depth: binder chemistry, mold substrate risk, moisture behavior, and what both manufacturers leave out.
Limewash vs Clay Plaster vs Mineral Silicate
Three mineral-based wall finishes compared: VOC and microplastic content, mold resistance, primer requirements, and moisture behavior.
Last reviewed: August 2026