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Hempcrete

Hemp hurd + lime binder — vapor-open, fire-resistant, and carbon-storing across the entire wall assembly.

Hempcrete — a natural material we specify on every Earth Bound Homes project

Toxicity Screening — All Clear

This material screens clear across all seven independent toxicology authorities we use on every project.

LBC Red List

Not Listed

Prop 65

Not Listed

IARC

Not Listed

NTP RoC

Not Listed

GSPI

Not Listed

REACH SVHC

Not Listed

TSCA

Not Listed

Material Type

Plant-Based Composite Wall Fill

Material Description

Hempcrete is a bio-composite of hemp hurd (the woody inner core of the hemp stalk) and a lime-based binder, cast wet into formwork between framing members. The result is a structural-infill wall material that's vapor-open, fire-resistant, insulating, and a net carbon sink across its life cycle — hemp grows fast, sequesters CO₂, and the lime binder absorbs atmospheric CO₂ during cure. R-value is moderate (~R-2 per inch) but the assembly's thermal mass and humidity-buffering give it real-world comfort advantages that exceed what its raw R-value suggests. Hempcrete is non-load-bearing — it fills around timber framing or a separate structural system.

Composition & Origin

Chopped hemp hurd (woody stalk core) + hydrated lime + pozzolan + water · cast-in-place between framing

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.

Cancer

1/10

Endocrine

1/10

Reproductive

1/10

Developmental

1/10

Neurological

1/10

Respiratory

2/10

Cardiovascular

1/10

Liver/Kidney

1/10

Skin

1/10

Immune

1/10

Common Forms & Brands

Tradical / Lhoist hempcrete binder systems
Just BioFiber pre-cast hempcrete blocks
Hempitecture HempWool (related but distinct insulation product)
Common framing: cast-in-place wall fill, pre-cast block, sprayed application

Why We Use It

Net carbon sink across full life cycle
Vapor-open assembly — exceptional moisture handling
Fire-resistant — lime binder is non-combustible
Termite, rodent, and mold resistant
Repairable and recyclable end-of-life

Where It Performs Best

Wall infill between timber framing members
Pre-cast block exterior wall construction
Roof and floor cavity fill applications
Insulating retrofits of solid masonry walls

Building Applications for Hempcrete

Listed alphabetically. Where in a home this material earns its keep.

Cast-in-Place Wall Infill
Floor Slab Insulating Layer
Pre-Cast Hempcrete Block Walls
Retrofit Insulation of Stone Walls
Roof Cavity Fill
Sub-Slab Vertical Edge Insulation

Specifying a project? Drop the manufacturer's SDS into our SDS Toxic Chemical Screener to verify any specific product you're considering screens clear on all seven databases.