Hempcrete Carbon Performance — Methodology & References
Hempcrete and GaiaCrete™ can be carbon-storing when measured against equivalent conventional walls. The two carbon sinks are biogenic CO₂ in the hemp hurd and ongoing carbonation of the lime binder.
Biogenic CO₂ in Hemp
Industrial hemp sequesters CO₂ during its 90–120 day grow cycle. When that hemp hurd is locked inside a long-lived wall assembly, the biogenic carbon is stored for the life of the building.
Lime Carbonation Over Decades
Hydraulic lime in the binder continues to absorb CO₂ from the atmosphere over the life of the wall (carbonation). Cumulative carbon uptake is included in published LCAs for hemp-lime systems.
Standards we reference
We frame carbon comparisons against equivalent fiberglass + OSB + spray-foam walls using methodology aligned with PAS 2050 and EN 15978. Carbon-negative claims here mean net CO₂e is below zero across the cradle-to-grave boundary defined in the LCA — not a marketing absolute.
See also: Proof hub · GaiaCrete™ · Hempcrete Insulation