Cellulose Insulation
Recycled newsprint and cardboard with borate fire treatment — the lowest-embodied-carbon insulation on the market.
Toxicity Screening — All Clear
This material screens clear across all seven independent toxicology authorities we use on every project.
Material Type
Plant-Fiber Recycled Thermal Insulation
Material Description
Cellulose insulation is ground recycled newspaper and cardboard, treated with borate for fire resistance and insect protection. It's the lowest-embodied-carbon mainstream insulation product available: roughly 85% recycled content, the manufacturing process is mechanical rather than chemical, and the borate treatment dosing is low enough that toxicity to mammals is negligible. Dense-packed cellulose achieves R-3.6 to R-3.8 per inch and forms an essentially air-tight installation, which is a major advantage over fiberglass batt for thermal performance in real-world conditions. EBH specifies cellulose for the majority of our retrofit and new-build wall cavity insulation.
Composition & Origin
Health Profile — All Endpoints Clear
Severity scored 0–10 against the same 10 hazard endpoints we use for the chemical families on the avoid list. Every score is 1–2 — essentially no signal across every endpoint.
Common Forms & Brands
- Applegate Cellulose
- Greenfiber Sanctuary & Cocoon
- National Fiber Cel-Pak
- Common framing: dense-pack, loose-fill blown-in, wet-spray cellulose
Why We Use It
- Lowest embodied carbon of any mainstream insulation
- Dense-pack installation is essentially air-tight
- Naturally hygroscopic — buffers cavity humidity
- Borate treatment is also a mild insect repellent
- Made from 85%+ post-consumer waste
Where It Performs Best
- Dense-pack wall cavities (existing and new construction)
- Loose-fill attic blanket
- Cathedral ceiling cavities (with proper netting)
- Sound attenuation in interior partitions
Building Applications for Cellulose Insulation
Listed alphabetically. Where in a home this material earns its keep.
Attic Loose-Fill
Cathedral Ceiling Cavity
Dense-Pack Retrofit Wall
Floor Joist Bays
Sound-Damping Partitions
Wall Cavity (New Construction)