What is Hempcrete?
Hempcrete- better known as Hemp Lime- is a building material that utilizes a hemp hurd aggregate and a natural binder to produce a lightweight concrete, which is used as an insulating material. This method and material has been increasingly recognized as a cost competitive and healthy alternative to conventional, toxic insulation materials. It is also generally used to replace standard drywall and siding materials in one clean installation. Hempcrete walls are a breathable, carbon sequestering, oxygen building system that create a healthy indoor environment. Hempcrete can be used to create healthy structures in any range from small off-grid cabins to commercial buildings.
This page is intended to help guide you to find the materials you need to build with hemp, and answer any basic questions you have
This page is intended to help guide you to find the materials you need to build with hemp, and answer any basic questions you have
Select your raw materials wisely
The Quality of a Hempcrete mix is directly correlated to the Quality of the Raw Materials used in the mix. When building with hemp, ensure that you use the highest quality raw materials possible. Excessive dust in your hemp aggregate can cause wall failures in the long term. Our purpose is to ensure a reliable supply of suitable hemp hurds for construction for all interested builders. All of our hemp hurds conform to the highest standards of professional construction, as established by the Construire en Chancre (CenC) label. The CenC certificate was developed in the birthplace of hemp concretes to create a professional and standardized level of Quality for hempshives for hempcretes. All of our hemp hurds comply with the standards set by the CenC label, carrying its label.
The Quality of a Hempcrete mix is directly correlated to the Quality of the Raw Materials used in the mix. When building with hemp, ensure that you use the highest quality raw materials possible. Excessive dust in your hemp aggregate can cause wall failures in the long term. Our purpose is to ensure a reliable supply of suitable hemp hurds for construction for all interested builders. All of our hemp hurds conform to the highest standards of professional construction, as established by the Construire en Chancre (CenC) label. The CenC certificate was developed in the birthplace of hemp concretes to create a professional and standardized level of Quality for hempshives for hempcretes. All of our hemp hurds comply with the standards set by the CenC label, carrying its label.
- -Controlled granulometry (Average Particle Size: 1/4"-1/2")
- -Minimal dust level (Rigorously Mechanically Dedusted)
- -Optimal moisture content
- -Constant Bulk Density.
- - Light Color (Synonymous with no mold)
Order Materials for Your Project
Find a Distributor list below, or order online and request a shipping quote.
For best value, it is recommended to order by the full truckload load direct to your job site. There are approximately 14.5 tons of hemp hurd per container (660 x 44 lb. bales). A full container would produce about 5280 cubic feet of wall (estimate only). To request a truckload quote, please fill out this form with as much detailed information as possible.
Chief Distributor
How to Make Hempcrete from our Hemp Hurds
To make hempcrete, Chanvra Core hemp hurds (the aggregate) are mixed with a binder. Most hempcretes utilize a lime binder, and Chanvra Core is validated with most lime-based binders in terms of performance required by the French Hemp Building Professional Rules. Our favorite binders are listed below, which include our very favorite: raw hydrated clay. Though this natural binder material requires a greater amount of work and attention to the drying process- and is less developed than the Hemp Lime method- it is a cheaper and more natural option that is well worth experimenting with! Whichever binder you choose, as long as you follow the instructions of the manufacturer, you can't go wrong with choosing Chanvra Core as your aggregate.
Binders
Pure Hydrated Lime
Hydrated lime (calcium carbonate) is one of mankinds oldest building materials. Once used by the Romans as a base for almost all building materials, it lost its importance and disappeared from the market when cement was invented. Now it is making a comeback! Hydrated Lime is a living material that can produce an alkaline in-door climate. This is caused by the constant carbonation process of lime (uptake of CO2). As water slowly evaporates from lime, CO2 is absorbed and the lime continues the carbonation process until eventually turning back to calcium carbonate. While our Chanvra Core hemp hurds perform the function of absorbing humidity from the air, the hydrated lime uses this moisture for carbonation. This makes these two materials an excellent match for a building product. Lime will eventually turn as hard as stone as long as the carbonation process continues.
Hydrated lime has one drawback: it cures (hardens) very slowly. To overcome this problem, a natural mineral additive has been invented that is able to speed up the initial setting time of the lime down to 2 days, without the lime losing its carbonation ability (mentioned above). This special formulated blend of volcanic minerals is made by one of our close partners and building mentors, and results in a curing time of 2-3 days with continued CO2 uptake.
- Reduces consumption of the basic binder from 60 to 25 kg per batch
- Produces a lower density material and weight reduction to 240 kg/m3
- A more porous product and therefore an improvement of thermal effect and humidity regulation
We sell these special minerals, and can also help you find close sources of hydrated lime. Request more info in the form below.
Raw Hydrated Clay
Some of the most ancient building techniques utilized just hemp fiber stalks and clay. Today, builders have the historically unique ability to make a modern hempcrete recipe utilizing just raw hemp hurds and hydrated clay.
How to Build with Hemp & Clay
Start by locating soil with a high clay content that can be ethically harvested. Avoid harvesting from virgin ecosystems in a way that causes damage- try to provide an ecological service with your clay harvest. Maybe there is a construction site nearby that needs to dispose of some clay fill. Better yet, try digging a pond for a permaculture project!
There are many videos and articles available on the internet about how to use a simple jar test to estimate clay levels in soils. Once you've located a good clay source, soak it overnight in barrels. Then, mix it up with a painters bit to produce a light, hydratec clay slip. Make sure the clay is not too heavy; you want a nice, light consistency like melted chocolate.
Mix the hydrated clay with high quality hemp hurds, using the same method you would use to mix hemp and hydrated lime. We recommend a vertical pan mixer. Or better yet, have your friends over and have a hemp mixing party! Unlike lime, clay is great for your skin, and mixing with your feet and hands is a rewarding experience!
Pack the Hemp Clay mix into your form system. Use the same best practices for formwork that you would use for Hemp Lime construction. Avoid over tamping. Hemp Clay requires even less tamping than Hemp Lime. Just a light tamp along the formwork will do. :Leave the material in the middle of the form completely untamped.
Spray Applied Hempcrete | The Ereasy System & binder
Available in the USA from our distribution partners, Americhanvre, the Ereasy system is a spray applied hempcrete that is helping scale up the hemp construction industry. Ereasy is made by BAUMER, an artisanal, family-owned masonry company, seeking solutions for the democratization of hemp concrete, in particular through the simplification of implementation. Since its creation in 2005, the company has mainly used natural and ecological materials such as Hemp, Lime and Prompt Natural Cement.
