Hempcrete Certification

Hemp Building Certification in The US

The purpose of this article is to bring more awareness to the current challenges facing the hemp building industry within the United States. Without the proper certification, the industry will stall and the amazing benefits of building with hemp lime (known as “hempcrete”)  will be limited. 


We encourage you to read this post in its entirety and to join the United States Hemp Building Association in its quest to certify and set building standards for hempcrete, hemp lime, and hemp building materials.  For additional details, please read the USHBA Certification White Paper.

A Brief Overview

The surplus of hemp for CBD is now turning many US farmers toward growing the plant for industrial purposes in 2020. Consumer awareness is rapidly increasing on the many benefits of hemp, particularly in the construction industry. Despite this, major hurdles still exist for the hemp building market to take off in the United States:


  1. Lack of processing equipment and infrastructure: Combines, harvesters, and other industrial equipment in the US does not have the throughput capacity to harvest industrial hemp at scale. 
  2. Lack of certification of hempcrete: Currently, building standards and performance measurement do not exist for the building material


While the equipment should work itself out when major companies (John Deere?) start entering the space, it is the certification challenge that will take the effort involvement of many people to overcome.

Who Is Leading The Charge?

The United States Hemp Building Association formed in July 2019 to achieve their goal of hempcrete / hemp-lime becoming internationally recognized certification. Some of the top experts within the industry are banding together to combine their knowledge, resources and networks to increase consumer awareness and generate enough funding to pay for certification. 

A special Education Committee within the USHBA is publishing the certification issues and documenting the process needed to obtain hempcrete certification as soon as possible.

What Are The Specific Challenges With Certification?

Per Dion Markgraaff and the USHBA Education Committee, hempcrete is meant to be a vapor-permeable wall system. This means that it allows passive transmission of moisture vapor through walls which then improves the thermal performance of the structure. The end result is a better indoor air environment for the inhabitants of the structure.

This incredible benefit of hemp lime also happens to be the existing challenge with certification and permitting within the US.  The hempcrete system was developed with European building standards, but US buildings are designed with a different standpoint on permeability.

Who Approves Certification? 

There are two organizations who will be responsible for the certification of hempcrete as a building material in the US. The USHBA is currently leading the charge to engage these groups.

1. The International Code Council (ICC)

The ICC provides standards for building systems, meaning they will determine how hemp lime can be used in a building. Current ICC codes typically require the use of vapor barriers in the building envelope and impermeable sheathing as structural bracing. Unfortunately, vapor barriers and impermeable sheathing impede the performance of hempcrete.

The ICC does have code appendixes that account for systems with high permeability requirements, such a Light Straw-Clay and Straw Bale. These systems happen to have similar permeability requirements to hempcrete, meaning the ICC has some sort of precedence and roadmap to work with to create such standards for the material.

2. The American Society for Testing and Materials (ASTM)

The ASTM provides standards for individual products, meaning they will determine how to define hempcrete and how to measure its performance.  Their current standards include testing for thermal, fire and permeability characteristics of building materials which can be applied to hemp lime.

Specifications must be developed to define what is considered hempcrete for the purpose of construction and building. What this means is that the physical characteristics of hemp hurd and lime binder must be specifically defined so that ATSM can develop the appropriate standards.  Additionally, performance standards that do not currently fit into ASTM testing standards must also be developed.

How Much Will Certification Cost?

The exact cost of certification is still being determined, but the initial estimates range from $20,000-50,000 for ASTM certification and $300,000-500,000 for ICC accreditation. 

It will require fundraising and grants from local/state organizations to effectively meet these costs for hempcrete to begin its accreditation process. 


How Can People Get Involved?

Joining The United States Hemp Building Association is the best way to get involved. Whether you are a consumer seeking to build a hemp house, a construction professional promoting green building, or someone who wants to preserve the world in which we live, there is a spot for you within the USHBA.  By joining, you will help to generate more awareness and funding to approve hempcrete as a certified building material. Only then will the US be capable of taking real steps toward building a better environment for our current and future inhabitants.