Chanvra Core: Building Grade Certified Hemp Hurds
What is Hempcrete?
Hempcrete is a building material that has been increasingly recognized as a cost competitive and healthy alternative to conventional construction materials. 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 large commercial buildings.
A Hemp Wall is Only as Good as the Raw Chanvra its Made From
The leaders of the international hemp building industry have determined that the Quality of a Hempcrete mix is directly correlated to the Quality of the Raw Materials used in the mix. The Construire en Chancre (CenC) label was developed to create a professional and standardized level of Quality for hempshives for hempcretes.
In other words, in the field of professional construction, we require reliable materials with a guaranteed performance. We cannot cut corners with building materials. In hempcrete construction in particular, we require materials with a reliably low dust content and consistent particle size. The CenC certificate is a guarantee of these necessary qualities, which include:
-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)
Our Chanvra Core (aka Kanabat) is the only brand on the US market grown to the Quality level demanded by the CenC certificate. And beyond, Chanvra Core is grown, processed, and stored to the highest standards in the world, with continuous internal and external controls to ensure reliability.
Order Materials for Your Project
We recommend finding a distributor near you to cut down on the costs of shipping. Find a Distributor list below.
Per pallet, there is enough hemp hurd for approximately 126 cubic feet of wall per pallet, depending on your mixing method and the binder chosen. Shipping quotes for pallets can be requested by filling out this form, and selecting "Pallet of Hempshives" in the "Product" field, and indicating the quantity.
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.
Chanvra Core: Building Grade Hemp Hurd, Pallet (21 x 44 lb bales) Shipping Billed Separately
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.
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 pure 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.
Ereasy: Spray Applied Hempcrete
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.