About Hemp and Hempcrete

Industrial Hemp

In 1937, Popular Mechanics magazine published an article on industrial hemp and they called it the “New Billion Dollar Crop.” That’s because it’s the incredible plant of 25,000 uses that can be grown, processed and sold on American soil rather than imported from overseas.

The products that can be made from industrial hemp rival those of the cotton, lumber, plastic and oil industries. You can make clothes, rope, paper, various food and oils, fuels, lubricants, paints, plastics and composites… heck, you can even build your own home out of industrial hemp.

And from the farmer’s field to the local textile factory, each product that’s made in the USA from industrial hemp is a new job created for our economy.

Additionally, industrial hemp can replace the lumber used for wood and pulp. It’s been reported that one acre of hemp provides as much paper as 4.1 acres of trees. (Dewey & Merrill, Bulletin #404, United States Dept. of Agricultural., 1916.)

Hemp also grows to maturity much faster than trees (months vs decades) and by using it we can preserve our forests.

Better still? Hemp can be grown without toxic pesticides, unlike cotton for instance, making it environmentally sustainable.

It’s for these reasons and more that hemp is playing a huge role in the “green revolution.” Hemp offers a way to live cleaner, healthier and more naturally while also helping to protect the environment that sustains us.


In particular, industrial hemp makes a fantastic building material. When used for building walls, as hempcrete, it offers:

  • long-term durability and strength
  • great insulation and thermal mass, reducing cooling and heating costs
  • resistance to bugs, fire, mold and pests
  • walls that absorb and damper sound
  • walls that “breathe,” helping to manage humidity, air quality and comfort
  • a natural alternative to conventional, toxic construction materials
  • the ability to recycle and reuse old hempcrete for new construction
  • and more

Hempcrete at its simplest is a mixture of hemp hurds (the woody, inner portion of the hemp stalk) with a lime-based binder and water. Using powdered lime is an ancient form of masonry with a reputation for longevity. As the lime-based binder cures, it sets back to its original form: limestone. And the hemp becomes “petrified” as well.

Above this, different types of pozzolans (small particles of volcanic rock with cement-like properties) and aggregates can be added to greatly alter the density, strength and purpose of the hempcrete.

For example, the mixture used for hempcrete walls is different than a floor mix. The wall mix is generally lighter and very “hempy” which increases insulation value, but also lowers compressive strength. On the other hand, a floor mix would be much denser, stronger and more durable but have lower insulation values.

Hempcrete walls are traditionally finished with a lime-based plaster or stucco, or other natural and breathable materials like wood cladding. This is why hempcrete walls can “breathe” and help prevent excess humidity and moisture from building up in the home. In contrast, modern construction materials are often designed to lock out (and therefore also lock in) moisture, which then requires more artificial circulation (fans, etc) to reduce the risk of mold growth and so on.

And although hempcrete is enjoying modern popularity, it has been used for centuries with success:

Isochanvre, a rediscovered French building material made from hemp hurds mixed with lime, actually petrifies into a mineral state and lasts for many centuries. Archeologists have found a bridge in the south of France, from the Merovingian period (500–751 A.D.), built with this process.

-The Emperor Wears No Clothes, by Jack Herer – Chapter 2

If you are looking for a healthy, natural and sustainable building material that can withstand the test of time, then hempcrete is for you!