‘HEMPCRETE’ IS A REVOLUTIONARY SUSTAINABLE BIO-COMPOSITE CONSTRUCTION MATERIAL THAT COMBATS CLIMATE CHANGE BY CAPTURING CARBON AND DELIVERING HIGH PERFORMANCE AIRTIGHT, INSULATING WALLS. HERE’S HOW IT WORKS AND THE MANY HEALTH AND ENVIRONMENTAL BENEFITS THAT IT CAN OFFER TO OUR LOCAL MAUI COMMUNITY
WHAT IS HEMPCRETE?
Along with bamboo, industrial hemp is among the fastest growing plants on Earth and can be used to make a wide range of durable and economical products — including paper, rope, textiles, clothing, biodegradable plastics, paint, biofuel, food and animal feed.
Not only this, but hemp can also be used as a sustainable building material, called ‘hempcrete’.
‘Hempcrete’ is a bio-composite material, developed from a mixture of hemp stalks, a lime based binder, volcanic ash minerals and water (this mixture can vary). The overall process creates a mixture that develops into a solid, but light and durable building block for construction and insulation.
WHAT ARE THE BENEFITS OF HEMPCRETE?
‘Hempcrete’ is a non-toxic, environmentally friendly building material, which is carbon negative, fire, mold and pest resistant, breathable, self-insulating and durable.
CARBON NEGATIVE
Hemp can help combat climate change, as it naturally absorbs carbon dioxide (CO2) from the atmosphere.
This CO2 is stored in the hempcrete building block after fabrication and for the duration of the block’s life, making hempcrete a ‘carbon-negative’ building material with positive environmental benefits.
NONTOXIC
Hemp is also an incredibly fast-growing plant, taking just four months to reach maturity and uses far fewer pesticides and herbicides than other grain or fiber crops, creating much less environmental damage due to the use of toxins on the fields.
This means that it it’s healthier for the inhabitants, with more ‘breath-ability’ than other building materials.
FIRE RESISTANT
Out of a flamedex index score of 0 – 450, with 450 being the most flammable, hempcrete scored 0, making it the most fire resistant building material on the market. Hempcrete can withstand direct fire for over 2 hours without igniting at all.
MOLD RESISTANT
Another amazing benefit of building with hempcrete is that it is mold resistant —which is especially beneficial to Maui residents living in rainier parts of the island. Because the hemp in hempcrete is mixed with a lime binder that makes it possible for the hempcrete to harden — the lime is what gives hempcrete its mold-resistant property.
TERMITE/PEST RESISTANT
While termites destroy approximately 600,000 homes in the U.S. each year, costing Americans over $5 billion annually to control and repair the damage — the good news is that hempcrete is also termite resistant.
SELF-INSULATING
The thermal properties of hempcrete are extraordinary as it allows for natural ventilation of the building, costing less money to heat or cool. Hemp insulates better than many other materials, such as cotton or wool.
DURABLE
Hempcrete is an incredibly strong and durable material, as the hemp cells hold lime and bind to themselves without a need for rebar or anything to hold them together.
BUILDING WITH HEMPCRETE
Michael Auldridge, of Michael Auldridge Design Works LLC, is a Master Craftsman who has traveled Internationally and is passionate about natural building design that promotes harmonious environments.
He is also an avid supporter and advocate for industrial hemp and ‘Hempcrete’, as a sustainable home building solution on Maui that could help provide a significant opportunity for our local communities.
When asked about his recent experience of building with Hempcrete during a workshop, Michael noted that “the only downside is that hempcrete can be more expensive to build with, as well as labor intensive.”
“This is mainly due to the process and because hemp is illegal to grow in most of the United States, so it has to be imported. What Maui really needs is our own hemp processing facility” said Michael.
Hempcrete Building Workshop / Photos by Michael Auldridge Design Works Llc.
ARE HEMPCRETE STRUCTURES CURRENTLY PERMITTED BY MAUI COUNTY?
While Hempcrete sounds like the obvious choice as a revolutionary building material to help solve our climate issues and build fast and sustainable dwellings for Maui residents — particularly during our rising housing crisis — the next question is whether the Maui Planning Department would actually permit building structures made from hempcrete.
To answer that question, it’s interesting to note that the first ohana and house built with hempcrete was in Kihei, Maui, designed by Architect George Rixey and contracted by Rixey Company INC., starting in 2015 and completing construction in 2017.
Kihei Hempcrete Home During Construction / Photos by Adam Rixey of RIXEY MAUI
Kihei Hempcrete Home During Construction / Photos by Adam Rixey of RIXEY MAUI
The Stunning Completed Kihei Hempcrete Home / Photos by Adam Rixey of RIXEY MAUI
According to Adam Rixey, “they went through the process to demonstrate that Hempcrete would be structurally sound and received a ‘conditional approval’ from Maui County for that specific building project, prior to starting any construction with the hempcrete materials.”
Even though their overall building costs were increased as the hempcrete couldn’t be sourced locally from Maui, they had to import it from Canada — the final home result proved to be stunning and worth the effort for the new owners, their health and our environment (see pictures above of the first hemp house built on Maui).
When asked if they thought Maui County would permit further dwellings built with hempcrete materials, Adam commented that “they did it once; it could be done again.”
WHAT DOES THE FUTURE OF BUILDING LOOK LIKE FOR THE MAUI COMMUNITY?
Most building and insulation materials used globally and throughout Hawaii today have remained the same for decades, and “can cause serious health and environmental issues from all of the toxic chemicals” said Michael, Master Craftsman of Michael Auldridge Design Works LLC.
“We need people to be more conscious of the environments that they are inhabiting and to move towards using building materials that work with nature, rather than against it — such as hempcrete — which means a healthier, more sustainable community for all of Maui” Michael concluded.
RESOURCES AND CREDITS
How Growing Hemp can Help Solve Our Climate Emission Problem
6 Advantages of Building with Hempcrete
The Benefits of Using Hempcrete in your Construction Projects
Five Amazing Ways Hempcrete Can Eliminate Sick Building Syndrome
A Home Building Revolution (Video)
Tour of First Hemp House on Maui
Construction Begins for Hawaii’s First Hemp House
Islands First Hemp Home to be Built on Maui
Building your Dream Home could Send you to the Hemp Dealer
CREDITS AND RESOURCES
Copyright NATIONAL ASSOCIATION OF REALTORS®. Article reprinted with permission. All rights reserved.