Hemp-lime (commonly called hempcrete) is a bio-based building material made from hemp hurd (the woody core of the hemp stalk), a lime-based binder, and water. It is cast or sprayed around a structural frame to form a vapor-permeable, insulating wall system. Unlike Portland cement concrete, hemp-lime relies on lime chemistry for binding and long-term mineralization. The lime binder carbonates over time, reabsorbing atmospheric CO₂ through a process known as carbonation. Key characteristics: • Non-structural insulating infill • Vapor permeable and hygroscopic • Fire resistant • Low embodied carbon potential • Compatible with breathable finish systems Modern hemp-lime construction began in France in the late 1980s and has since been adopted across Europe and North America. It is now recognized in U.S. building codes under the 2024 International Residential Code (IRC) Appendix BL.

The terms are used interchangeably in North America. Technically, “hemp-lime” is more accurate because the binder is lime-based rather than cement-based. The term “hempcrete” emerged as a shorthand to describe its cast-in-place application method.

No. Hemp-lime is not typically load-bearing. Structural loads are carried by an independent frame system such as: • Timber frame • Light wood framing • Steel framing • Engineered wood systems Hemp-lime functions as: • Insulation • Air control layer (when detailed properly) • Moisture buffering layer • Acoustic dampening system Structural performance is engineered separately.FAQs can be added to any page on your site or to your Wix mobile app, giving access to members on the go.