A rose by any other name...

Over the past month, I’ve been weighing the nomenclature used for a hemp and lime-based binder, a biocomposite mixed mass, commonly known as hempcrete. I’ve been evaluating the term against hemp-lime, or in my case, hemp+lime.

I particularly liked the + plus symbol, as it feels inclusive and acknowledging, rather than subtly negating.

After much consideration, an international dialogue with many of the leading minds in the world on this biocomposite, and multiple calls with Alex Sparrow of UK Hempcrete to engage in lively debate on the subject, I’ve come to terms with the term hempcrete.

Hempcrete is in

These calls culminated in a soon-to-be-published co-authored article for the US Hemp Building Association What’s in a Name - article by Alex Sparrow and Jennifer Martin, in the hopes that others might benefit from the time and attention that we put into this quandary. Ultimately, we came away from the exchange clear that:

a) The ship has sailed, proverbially speaking, around the nomenclature most likely to gain market attention. Both hempcrete and hemp-lime have been in use for 20 years - hemp-lime being the original name (directly translated from French), so has been around even longer - yet hempcrete has become the term popularized by media, the media, and enthusiasts alike.

Alex made a great point that didn’t get into the article, which is that you know it’s entered the mainstream consciousness when Steve Bannon touts a plan to build a wall at the US-Mexico border using hempcrete. Good point.

b) Hempcrete makes a good deal of sense once you know the details of binder chemistry, all of which need minerals in addition to pure lime to provide the hydraulic set for this biocomposite mass.

c) Couple that knowledge with a definition of concrete as a generic term rather than a particular material (think paper tissue instead of Kleenex), and hempcrete is clearly more accurate than hemp-lime.

Concrete (noun):

1 : a mass formed by concretion or coalescence of separate particles of matter in one body

2: a hard strong building material made by mixing a cementing material (such as portland cement) and a mineral aggregate (such as sand and gravel) with sufficient water to cause the cement to set and bind the entire mass

Source: Merriam Webster

d) We have bigger fish to fry than debating endlessly about word choice, as there is an nearly endless list of tasks associated with starting a new industry.

what begs to be said:

Even though we’ve walked away clear about where to go with terminology, there are some valid points made in my internal process that I believe are worth mentioning here.

For context, my starting point was frustration with the endless circular reference conversations that I’d observed or been involved in. They went something like this:

Wait, there’s no portland cement? Lime - what is lime? Ok… but no rock? Hemp as a aggregate? What - how? But doesn’t that rot? How does this all work again? 

And finally - then why is it called hempcrete?

By using the term hempcrete, we face a ubiquitous common understanding of the material concrete as a structural, sub-grade material.

Popular convention assumes concrete to mean portland cement concrete, made with sand and gravel or stone aggregate, which has very different vapor permeability properties than hempcrete.

It’s quite reasonable for someone new to hempcrete to assume that the aggregate - identified clearly as hemp (instead of con with the associated negative connotation) - is the only variable that is different from concrete. In fact, both the hempcrete binder and the aggregate are different from concrete. This results in mass confusion, in particular because concrete and hempcrete are both lime-based binders that perform very differently.

Nuance is everything

This bio-composite is rather simple, yet complicated to understand because hemp and lime are not commonly thought of as building materials. Even though concrete is predominantly lime-based, it uses a mix of minerals that are commonly referred to as cement. Unless you are in the business of making or interfacing chemically with concrete, it’s likely that this distinction is not clear. Since we are testing local lime mixes for use in hempcrete, this education has been vital to our work, and this understanding helps when explaining the nuances of hemp and lime-based biocomposites.

It takes a somewhat sophisticated understanding of lime to capture the nuances of changes to lime properties when heated to different temperatures and/or is combined with other minerals. I’ve been studying this for a few months, and I am still on a learning curve. IT has felt unfortunate that we don’t have this deep knowledge embedded in our culture. A large portion of the building industry and the general public will face some amount of the learning curve I have experienced.

Learning Journey

What has helped me tremendously is thoughtful, articulate, clear, and universally-understood educators that can communicate the properties crucial in hempcrete. In my journey of learning, I have gained the most from the the way that Alex Sparrow communicates about hempcrete.

Alex co-authored The Hempcrete Book, a very thorough book about hempcrete, and The Extract published a 10 minute video of Alex explaining and demonstrating hempcrete on a trade-show floor.

Further insights won

Public perception, in lay terms and professional circles alike, overwhelmingly associates the term crete with concrete, and concrete to portland cement-based concrete, as it is ubiquitous.

If we were to be precise, most concrete is actually portland cement concrete.

In concrete’s path through history, portland cement is still an infant. Hydraulic Lime Concrete has been used since Roman times; the 2000 year old Pantheon is built with it. Comparatively, portland cement (comprised of lime and additional minerals, heated at a higher temperature than hydraulic lime to create) has only been around for 200 years. 

Continuing with precise language, most hempcrete made today would be a hydraulic lime hemp concrete.

What it took to get here

I felt ready and willing to embrace the term hempcrete once I:

a) learned more about the origins of the nomenclature used to describe this biocomposite, and

b) better understood the properties of concrete and lime containing the cementitious properties needed for concrete, and

c) integrated the general term for concrete.

What’s in a Name?, the article co-authored with Alex Sparrow of UK Hempcrete, takes a dive into each of these points, and comes away with some guidance to grow public awareness,  ensure market adoption, and develop the industry in order to change the world. We hope you check it out, and we’re interested in having your voice in the mix.

I’ll admit, I do miss using a + plus simple to describe a new favorite natural building material, but I’ve let it go, now that I know that hempcrete is much more accurate. That said, I’ll happily respond to your questions about hemp+lime any day.

Because after all, a rose by any other name would smell as sweet, and a house made of hemp would still save heat! - anonymous