IRC APPENDIX AY HEMP-LIME (HEMPCRETE) CONSTRUCTION PROPOSAL

This page is a repository for supporting documents for code change proposal RB316-22, APPENDIX AY HEMP-LIME (HEMPCRETE) CONSTRUCTION (8646), for the 2024 International Residential Code (IRC).

On this page you will find the code proposal, testing reports and analysis, research papers, professional and academic journal papers, and other references.

RB316-22 proposes to add Appendix AY to the 2024 IRC. It was submitted to the International Code Council (ICC) in January 2022, and will be heard at the ICC Committee Action Hearings (CAH) by the IRC Building Committee between March 27th and April 6th in Rochester, NY.

Please direct inquiries to Jacob Waddell: Jacob@USHBA.ORG or at 720-263-0667

PDF of the submitted Proposal:
Proposal RB316-22 – Appendix AY HEMP-LIME (HEMPCRETE) CONSTRUCTION

Supporting Documents by Category:

Hemp-Lime Overview

• Hemp + Lime; Examining the Feasibility of Building with Hemp and Lime in the USA, Healthy Materials Lab at Parsons School of Design, 2020 – This guide provides an introduction to the history of hemp and its uses, and explores the production of hemp-lime blocks for projects in the USA. 
• Tradical Hempcretes – This brochure provides an overview of hemp-lime and its performance characteristics, as well as technical specifications for this proprietary product.

Videos

• This episode of the BUILD Show provides an overview of hemp-lime, its uses and fire resistance potential, and some of the different methods which can be used to install it.
  • https://www.youtube.com/watch?v=cm23l_VLyp4 
• This video shows the mixing and application of hemp-lime plaster while discussing some of it’s benefits.
  • https://www.youtube.com/watch?v=sDa_ZiB91ek 

Structure

• Verdant Structural Engineers: Structural Calculations for Hemp-Lime IRC Proposal

Fire Safety

• ASTM E84 Testing on Hemp Lime Biocomposite(Hempitecture) – ‘Intertek’ test of surface burning characteristics (smoke-developed and flame-spread indexes) conducted on hemp-lime specimens. 
• ASTM E84 Testing on Hemp Lime Biocomposite (American Lime Technology)– ‘Intertek’ test of surface burning characteristics (smoke-developed and flame-spread indexes) conducted on hemp-lime specimens. 
• Steve Allin’s fire test video: https://www.youtube.com/watch?v=FeW6kuZgPY4
  • This video demonstrates the fire resistance abilities of hemp-lime. Though this code proposal does not claim a fire-resistance rating, an ASTM E119 test is planned in the near future.

Mechanical, Moisture, and Thermal Performance

• “Mechanical, Thermal, and Moisture Buffering Properties of Novel Insulating Hemp-Lime Composite Building Materials,” Yaser Abdellatef, Mohammad Amil Khan, Asif Khan, Mehdi Iftekharul Alam, and Miroslava Kavgic, Materials, 2020  – This study aims to develop and understand the properties of hemp-lime made with innovative binder mixes of pozzolans, including the mechanical and hygrothermal properties, and factors which affect compressive strength, thermal conductivity, and specific heat capacity.
• The effect of different mix proportions on the hygrothermal performance of hempcrete in the Canadian context. Ujwal Dhakal, Ryerson University, 2021 – This study aims to understand performance characteristics of hemp-lime based on particular ratios of binders as a way to understand the hygrothermal behavior relative to wall thickness and required R-value.
• Bioclimatic envelopes made of lime and hemp concrete, Arnaud Evrard and André Herde, CISBAT 2005 – This paper presents hemp-lime as a sustainable building material suited for wood-framed structures, and highlights three case studies of its hygrothermal characteristics.
• Thermal Conductivity of Hemp Concretes: Variation with formulation, density and water content, Florence Collet and Sylvie Prétot, Construction and Building Materials, 2014 – This study investigates the effect of formulation, density and water content on the thermal conductivity of hemp-lime.
• Thermal Properties of Hempcrete, a Case Study, Jere Komsi, Helsinki Metropolia University of Applied Sciences, 2018 – This thesis explores the thermal characteristics of spray applied hemp-lime through available literature and practical tests.

Supporting Books

The following books were used in the creating the proposed Appendix AY and support its provisions. However, the books are for sale only by outside entities.

• Building with Hemp – Covers the origins and utilization of hemp-lime in construction as well as the latest developments and case studies.
• Bio-aggregate-based Building Materials – An overview of the material properties of construction materials made of plant particles, including the hemp plant.
• Hemp Lime Construction: A Guide to Building With Hemp Lime Composites – Case studies and design details on the uses of hemp-based materials in the construction industry.
• Essential Hempcrete Construction: The Complete Step-by-Step Guide –  A complete introduction to hemp-lime and its uses.
• The Hempcrete Book: Designing and Building with Hemp-Lime – An overview of construction techniques with a comprehensive resource section and case studies.

Supporting Documents in French

Many of the publications found on the Construire en Chanvre documents page were used in creating the proposed Appendix AY and support its provisions. However, these resources are currently available only in French. Modern hemp-lime construction originated in France, so much of its development has occurred there. Construitre en Chanvre is the French association for hemp builders and advancement of the industrial hemp industry in France and Belgium, and institutes it’s own professional regulations in this field. 

Documents found on this site include fire safety testing, rules of construction, background information on the properties of hemp-lime, models of hemp-lime performance and more.

A team member for the hemp-lime construction IRC proposal is fluent in French and received considerable input from longstanding French practitioners.