We were fortunate to visit a site in central Texas where they are using a hempcrete in the wall assembly, to surround a roughly 400 year old Japanese timber frame structure. Huge thanks to Mattie Mead, who founded Hempitecture, an Idaho based company bringing hempcrete and hemp wool insulation to the American market, for taking time to show us this project.
Hemp has gotten a bad wrap over the last century thanks to its medicinal cousin. But from the sound of it, we should be seeing more and more applications of hemp here in the states, as it is a bomber agricultural commodity with so many applications. Hemp Shives; processed from Hemp Stalks (waste material) are now being used to create sustainable building materials; like Hemp-crete, Hemp Plaster, Hemp Wood and more…
What is Hempcrete?
Hempcrete utilizes the core of hemp plants in a woodchip like form as the aggregate, combined with natural binders, and water to achieve the finished product.
Hempcrete is a bio-aggregate concrete, where the hemp shives – small pieces of wood from the stalk of the plant – are mixed with either a lime or mud cement to create a durable, eco-friendly building material. Hempcrete is lightweight and non-structural, but can easily be integrated with traditional building construction systems. Similar to traditional concrete, it can be either cast-in-place or prefabricated into building components like blocks or sheets.
Hemp is one of the oldest crops domesticated by humans. With its wide variety of uses and applications, it’s easy to understand why it’s been a desirable product throughout history. Hemp seeds and flowers are used in health foods, medicines, and organic beauty products; the fibers and stalks of the hemp plant are used in clothing, paper, and biofuel. Because hempcrete is made from natural waste material, its entire life cycle as a building product is environmentally-friendly, all the way to its eventual reuse or recycling in the case of demolition. Even the cultivation of the hemp plant requires less water, pesticides, and fertilizer than other crops.
Hempcrete is Sustainable
Hemp has been used in various forms of construction dating back to the Romans, in bridges, sails, ropes, and now more recently in residential construction. Reintroduced first in Europe, Hemp construction takes form as a low weight, high insulating, vapor permeable wall component.
Hemp is easy and quick to grow in almost any part of the world and provides two harvests per year. As it grows, it sequesters CO2, prevents erosion, naturally stops weed growth in its surroundings, and also detoxifies the soil. What is left after harvest breaks down into the soil, providing valuable nutrients and making hemp a desirable rotation crop for farmers.
Once cast, hempcrete requires significantly less water than traditional cement to cure, contributing to the preservation of this precious natural resource.
Hempcrete is a Carbon Negative Material
The high silica content found naturally in the woody parts of the hemp plant means it bonds well with lime. The lime binding agent used in hempcrete is in the form of calcium hydroxide, which absorbs carbon dioxide from the atmosphere to create calcium carbonate, or limestone. This means hempcrete is not only durable, but actually a carbon negative material.
Hempcrete Increases Health & Safety of Buildings
In the case of a fire, the lime coat provides adequate fire-resistance for the occupants to evacuate – because it burns locally and without smoking.
Hemp based building materials reduce both the spread of fire and the risk of smoke inhalation.
Its lightweight structure and the air pockets created among the particles mean hempcrete is both earthquake-resistant and an efficient thermal insulator.
Hempcrete is naturally resistant to both mold and pests, won’t cause any skin or respiratory problems and is also vapor-permeable, creating a healthy indoor environment.
Making hempcrete a more widely accepted and used building material could have economic and social benefits as well as environmental.
1500 years ago humans were making use of these particular properties. –
Many people know at least one artist who seeks inspiration from the use of recreational drugs. What may surprise people is the new study that shows how cannabis was used to preserve the artwork found within ancient caves in India.
A research team led by Indian scientist M.R. Singh, found Artwork in India’s sacred Ellora Caves; from the 6th century CE, that has been almost perfectly preserved… largely due to the ancient people’s use of hemp plaster. – These artists had crushed the hemp plant and mixed it with lime to form a plaster. Read Article
Hemp’s natural ability to repel pests and regulate humidity means that the artwork in these caves survived the test of time; while that of the Ajanta Caves, built before those of Ellora and not utilizing hemp in their plaster, was eventually destroyed primarily by silverfish insects. Read Study
Project – Central Texas https://www.hempitecture.com/theminka
Mattie Mead – Hempitecture https://www.hempitecture.com
Chad Burnel – EIM inc. – Builder http://eimtxcorp.com
Axel Vervoodt – Architect https://www.axel-vervoordt.com/interi…
Mell Lawrence – Local Architect http://www.melllawrencearchitects.com
Seth Willison – Timber Frame Designer https://www.willisontimberworks.com