Gallery: Hemcrete®: Carbon Negative Hemp Walls


Buildings account for thirty-eight percent of the CO2 emissions in the U.S., according to the U.S. Green Building Council, and demand for carbon neutral and/or zero footprint buildings is at an all-time high. Now there is a new building material that is not just carbon neutral, but is actually carbon negative. Developed by U.K.-based Lhoist Group, Tradical® Hemcrete® is a bio-composite, thermal walling material made from hemp, lime and water. What makes it carbon negative? There is more CO2 locked-up in the process of growing and harvesting of the hemp than is released in the production of the lime binder. Of course the equation is more complicated than that, but Hemcrete® is still an amazing new technology that could change the building industry.

Good looking, environmentally friendly and 100% recyclable, Hemcrete® is as versatile as it is sustainable. It can be used in a mind-boggling array of applications from roof insulation to wall construction to flooring. Hemcrete® is waterproof, fireproof, insulates well, does not rot [when used above ground] and is completely recyclable. In fact, the manufacturers say that demolished Hemcrete® walls can actually be used as fertilizer!

Available for years in the U.K., Hemcrete® is only now finding its way into North America. The species of hemp used to manufacture Hemcrete® is illegal to grow in the U.S., making Hemcrete® an expensive option for U.S. builders for now. As pressure for more sustainable building materials grows, lawmakers are certain to revisit this and other similarly restrictive statutes, particularly if there is money to be made. And judging from the success of Hemcrete® in Europe and elsewhere, there is plenty to be made; it is so profitable overseas that Hemp Technologies, one of the biggest manufacturers of hemp products in the UK, is actively recruiting as many new growers as it can.

+ Tradical Hemcrete


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  1. Up YERZ, DUPONT!!!!!!!!... August 31, 2014 at 12:05 pm

    […] […]

  2. raycooper June 6, 2014 at 10:05 pm

    Van I purchase a hempbrick for demonstration and inspection purposes.
    Also is there a supplier in Canada

  3. HempAuthority December 5, 2013 at 5:58 pm

    Hemcrete has such amazing potential. One of the strongest reasons for the freedom to grow hemp in the United States. We hope to some day have our company headquartered out of a hemp building! Check us out at

  4. arkitrekker March 9, 2013 at 7:25 am

    Why does the URL for this article claim that the hemcrete is 7x stronger than concrete? Stronger in what respect?

  5. suenos May 6, 2012 at 9:15 pm

    In all this debate and comparison of hemp to concrete no one really has said anything about the horrific realities of making concrete from Normal Portland Cement. For every ton of cement 80% of that weight is produced in CO2. So when one wants to make comparisons to this product as some kind of ideal lets not forget it is in reality one of the greatest environmental offenders on the planet if not the absolute worst. Few products have an 80% waste factor to their credit. Also do not forget the cement industry is one very cozy cartel that is controled by a very small group of very wealthy and very powerful people. Hence that basis of reality directly leads to some of the brainwashed BS comments we have read on this blog.

  6. innovator42 March 12, 2012 at 7:23 pm

    Its ridiculous that the US maintains a huge volume of prescriptive regulations (including banning the farming of industrial hemp) each of which effectively squashes innovation – whatever the problem is. I have no issue at all with outcomes-based regulations (which we do indeed need) but to prescribe HOW to do things only makes it harder for the US to be that innovative culture it dreams about.

    Some of the comments on this site underscore the skepticism about anything innovative (even when its been re-invented). Decades ago RCA gave away its flat screen TV technology to Japan because RCA management was fixated what a TV set was supposed to look like. We’ve been paying a heavy price ever since for that kind of corporate myopia.

  7. NRSsaving April 1, 2011 at 10:00 am

    Here in the UK I’ve become involved with a company that has the license for a new variation of a hemp building product. This is a timber frame/hemp block system. The hemp block encases the timber frame and can be therefore be used for any design. U values are 0.15 and the properties of the block means that the structure can breathe. Thus regulating temperature and humidity and creating a better environment for the end user.
    If any one would like more information please go to and take a look.

  8. WeBuildGreen January 18, 2011 at 11:16 pm

    For all your GREEN home needs

    Green Planet Building of Los Angeles
    11965 Venice Blvd., Suite 203
    Los Angeles, CA 90066


  9. montyp December 4, 2010 at 4:03 am

    economics, as always with any transaction, will dictate if this product grows into regular use. the strongest power for changing restrictive statutes is denying your purchasing power from companies whose products are destroying the Earth. Taking a re-usable bag with you when you shop s a first step, a second step is informing yourself about the owners of the products you do ‘buy’, if enough ‘potential purchasers’ desert an established product and create the demand for a ‘new’ (more sustainable) one ….economic power will bring it into production. So I repeat again, you have the power to change a society you don’t approve of, you carry that power in your back-pocket

  10. Lodhizattva October 30, 2010 at 2:14 pm

    This type of Hempcrete definately has its applications. Similar to concretes, ‘hempcretes’ have different ingredients depending on intended use. Concrete is made differently for sidewalks as opposed to load-bearing and pre-stressed beams, so is large-pour concretes. Check the chemical and mechanical properties first before opening your mouth/blog window to avoid misinformation and presenting yourself as ignorant.

    The best way around the downfalls of ‘cellulose’ and organic properties that are not desireable for certain applications, just petrify the organics with a lime process or similar. A little knowledge can go a long way, and not only make better products, but make blog entries and replies less painful to filter through; if they would exist at all…

    Aloha no, gotta go…

  11. eric cruz October 9, 2010 at 3:07 am

    will it be possible or economical to import to the philippines the processed material so we can have cheap substitute for concrete for our housing projects for the poor?

  12. moviehouseboy September 24, 2010 at 12:33 pm

    Does Canada Have any Dealers?

    Can you smoke it?


    jim in Kawartha Lakes

  13. Dude! Canada to Build a... August 24, 2010 at 2:25 pm

    […] one way to get college students to go to class: assign them to build things with cannabis. Several Canadian companies are teaming up with polytechnic schools in Alberta, Quebec and Toronto […]

  14. Scotts_Contracting July 20, 2010 at 12:19 am

    Great Idea. Love the Green and Eco Friendly Product. I\’ll offer a free article submission at my green web site: Build Green Scotty

  15. SpliFF June 3, 2010 at 1:53 am

    I’ve done a lot of research on this including visiting hemp farmers. I’ve seen, held and tested samples of different hemp manufacturing techniques such as ‘hemp paper’, ‘hemp board’, ‘hemp fibreglass’ and ‘hemp plastic’ created by extruding hemp cellulose or using fibres, often in combination with other materials.

    Having seen the flexibility of hemp as a raw material I have an issue with people confusing the virtues of a single product like ‘hemcrete’ with the hemp industry as a whole. Ultimately the properties of one manufacturing technique says very little about the usability of hemp in construction. It is entirely possible to create stronger materials than concrete out of, or in combination with hemp. Again I have seen these materials.

    There is a scientific basis behind hemps strength. Firstly hemp is approximately 70% cellulose – which is natures glue and the basis of plastic. Secondly it has long, very strong fibres which form the basis of reinforcement in fibreglass and many building materials. It isn’t the only plant with these properties but it is generally easy to grow, requires few chemicals and is capable of being selectively bred to enhance desirable properties.

    Which brings us back to why it isn’t used. When hemp was banned it was entirely due to DuPont Chemical manipulating the US treasury. It was done to protect his interests in cotton, synthetic fibres (hemp was banned in 1938, the same year nylon was patented) and timber interests. The simple truth is powerful lobbies for timber and chemical industries have conspired to keep it out of the public’s reach ever since. Big business fears nothing more than regulation and competition and hemp is competition. It will never become legal in America as long as these lobbies have such power.

  16. keepitsimple January 6, 2010 at 1:48 pm

    Have you seen the video on the hemp car? check it out. henry ford built it a long time ago. I am canadian and a farmer, a naber of ours grew a small plot of hemp a few years back. It cost a shit load to grow, well not to grow but to have cops and gov people patroling the thing 24/7. we stoled about 10 plants made us a big batch of oil out of it. 5 gal. of iso and not a drop of oil. plus if you tryed to hide a real pot plant in the crop it would just cross bread and go male. google the hemp car thing.

  17. Shodo December 31, 2009 at 10:02 am

    In the 1940’s (maybe 30’s) there was a campaign by other textile industries to outlaw industrial hemp, associating it with marijuana. Industrial hemp looks nothing like a m.j plant, and if they interbreed the product makes people nauseous when smoked. So it was a bald like.

    I assume that Hemcrete uses industrial hemp.

    A few years ago the state of Minnesota (under Gov. Jesse Ventura) legalized some experimental growing of industrial hemp. I don’t know what ever came of that, but it would be interesting to find out. Hemp involves very few chemicals in growing, even non-organically, and has other environmental benefits.

  18. Frateco December 1, 2009 at 2:37 am

    Folks, am late making these comments but ….

    It’s comments by people who don’t know eg Dead Unicorns that make eco products a hard thing to promote.

    Here’s the facts: Hempcrete is NOT 7x stronger than concrete. It does have loadbearing capacity but it’s not high. In fact, it can be loadbearing but it’s sometimnes easier just to say use it in non-loadbearing situations.

    I have certification to say termites will not touch hempcrete, will not burrow through hempcrete so Dead Unicorns … GET YOUR FACTS STRAIGHT!!

    Chrisp68 got it right – don’t compare it to concrete. It performs way better than concrete as a thermal insulator and relative humidity regulator. It is fire resistant, it does ‘breathe’ meaning it will allow vapour to phase change and then release.

    Go to for great tech details.

    Let me finish with this:

    We are all looking to improve our lifecycle carbon output using insulation batts and recycled materials (eg recycled concrete) but if the carbon you save is less than the carbon output to make these products, aren’t we just kidding ourselves???

  19. Hemp_4_Victory October 22, 2009 at 11:02 pm

    Hemp is very useful and was outlawed (labeled as marijuana) due to money, Politicians are afraid to try and make it sound good, after 70+ years of lies, propaganda, and rhetoric about how bad/dangerous this plant is from the government.

    Good documentary narrated by Woody Harrelson

    Video made during WWII from United States Department of Agriculture, 1942 Hemp for Victory

    One of the most informing books on Hemp/Marijuana (The Emperor Wears No Clothes), and you can read it for free online.

    $100,000 Challenge to Prove Us Wrong!

    If all fossil fuels and their derivatives, as well as trees for paper and construction, were banned in order to save the planet, reverse the Greenhouse Effect and stop deforestation;

    then there is only one known annually renewable natural resource that is capable of providing the overall majority of the world’s paper and textiles; meet all of the world’s transportation, industrial and home energy needs, while simultaneously reducing pollution, rebuilding the soil and cleaning the atmosphere all at the same time…

    and that substance is the same one that has done it before . . .


    Hemp is of first necessity to the wealth & protection of the country.”
    – Thomas Jefferson

  20. keentolearn September 7, 2009 at 12:11 am

    Hey Dead_Unicorns,

    Would like to hear more from you regarding your negative comments on Hemcrete.
    What are you judging by? Is it personal experience or internet research?

    Hope you get back to me.

  21. Ed Saukkooja September 3, 2009 at 11:13 am

    Noted by the retreat of our President concerning all things cannabis, it is evident big money and power are continuing to prohibit any industry from developing around the hemp or marijuana cultures. Once we as a nation are reduced to a third world status, hemp will be our only recourse.

  22. bliss tick August 29, 2009 at 8:24 pm

    Concrete will be replaced to some degree in time and jobs will be lost only to be replaced by new jobs. Anyone in the building trades including product manufacturing are wise if they stay up to date with technology and need. If the concrete industry is blind then they will find themselves in a hole in the ground. Maybe they could use the influance they have to promote and establish any alternatives that will arise so they will benifit and help to strengthen their comunities rather then turn to dust or rust. Peace power.

  23. chrisp68 August 27, 2009 at 8:13 pm

    Then it should not be compared to concrete! It should be compare to stress skin panels instead. Just make large insulated walls of this stuff instead. Get the story and comparisons correct before the article is published!

  24. bloo August 25, 2009 at 10:16 pm

    Hey UNICORN, why don’t you throw out some references, as to where you come up with your fascinating information there?!?
    Go take a bong hit now or something…..

  25. Daniel Flahiff August 25, 2009 at 8:27 pm

    Hello all,

    My apologies for the strength statistics quoted in this article. My research indicated that the product was in fact 7X stronger than concrete, information reported by seemingly reputable sources, but it appears not to be the case. Here is an update from Ian Pritchett, Chairman and Technical Director of Lime Technology Limited:

    “Hemcrete® is not a direct replacement for concrete. It is a bio-composite, thermal walling material (or other insulation material). Hemcrete® is not stronger than concrete. In fact it is usually used in a non- structural way, along-side a structural timber frame. Hemcrete® is about 15% the weight if concrete. The hemp in the Hemcrete® does not deteriorate because it is preserved by the lime in the binder, but it is only used above ground with fully breathable finishes.

    Many thanks

    Ian Pritchett
    Chairman and Technical Director
    Lime Technology Limited”

    Sorry again for the confusion.


    Daniel Flahifff

  26. Weeble August 25, 2009 at 4:37 pm

    Has the product been investigated by ASTM? I would believe their statistics / properties without question as they are based on standardized tests for flame spread, compressive and tensile strength, mold resistance, r-rating etc. It would be a no-brainer if it could replace the tobacco industry and, the other legally produced products associated with “hemp” would add a significant economic spark to a region that could use it. You can only have so many golf courses! It could be used in non-structural applications until adequate research is available to document strength properties. I am sure we can bio-engineer an inert form of the plant to appease the fear associated with the illigal aspects. I’m not inclined to “just say no”, given the great many potential benefits of a product like this – but I have to have real numbers before I risk using it in any structural application. By the way, I think the jury is still out on our claim to have “improved” over the construction materials used for the Great Wall and Pyramids – cheaper, faster, more abundent – but “better” is still up for grabs.

  27. Knighted428 August 25, 2009 at 4:23 pm

    This “Birkenstock wearing granola cruncher” is also a designer and Architect who specializes in Green Tech ain Colorado. This product will be in demand in my market. We are all looking at ways to lower the carbon footprint and it starts when you build your home. This looks better than some of the pressed sunflower seed products we already use and much stronger too. I need a sample!

  28. willow_256 August 25, 2009 at 3:47 pm

    Not a chance this stuff is stronger than concrete in tension or compression. The website lists a strength of around 0.9 to 1.1 Mpa for the insulating mixtures. Thats roughly 150 psi, with most concrete at 4000 psi as an industry standard. So for compression this stuff is 27 times “weaker”. As for tension, a 4000 psi concrete would have a strength of roughly 475 psi, so again magnitudes stronger. But no structural engineer would design concrete to go into tension, hence the use of rebar.

    Bascially, the only structural value is that this stuff would replace wood or GWB sheathing for shear wall applications. Vertical bearing wall loads and out of plane wind loads would need to be resisted by traditional methods. The kicker is that it looks like it needs to be formed, which creates lots of waste on construction sites and costs a lot in material in labor. I don’t see any advantages.

  29. Trey Farmer August 25, 2009 at 2:50 pm

    There is a pretty good and brief history of our global prohibition on hemp. It is pretty absurd. But if this product gets use in the US it will put a lot of money into Canada, maybe then we will shift our laws.

  30. jglass August 25, 2009 at 1:24 pm

    Anyone know about anything similar to Hemcrete, or aspaltic in nature, for roadways?


  31. greennoblework August 25, 2009 at 1:14 pm

    YES!! I’ve heard of experiments with hemp products being permitted in the US. through the issuance of special government permits to university researchers, so any of you in graduate schools or with connections could press for more of this until we can get the foolish ban on hemp undone. I’m concerned however, that our current ways of government and money system may come undone before this can be achieved.
    I understand from my Green Conferences and Bioneers attendances that the state of Kentucky still has portions of the hemp collectives used back when it was legal and used to make garments, food (and the first flag) in early U. S. history, so it could more easily be grown there with growers sharing the know how and needed equipment. It WOULD indeed be a great boon to our economy as others have commented and would a step towards furthering a much needed appreciation, hopefully even sacred regard, as Native Americans had, for our mother earth. This latter quality, the OCCUPATION really, of Earth Steward or caretaker is one I’d like to see us all aspire to more, realizing that our own bodies are microcosms of Earth. This is much needed to transform and heal our, so called, Western Civilization, with it’s Romanized version of Christianity, essentially devoid of the sacred feminine, our Earth, Health Care System, and ourselves, our own bodies and minds. Care and Committment are key to making this happen.

  32. dukie564 August 25, 2009 at 1:12 pm

    This article is extremely misleading….this product cannot be used in compression and therefore in structural situations….therefore you cannot compare it to concrete…especially with respect to it’s strength.

    It’s possible it is 7x stronger in tension…but that is irrelevant to concrete since unreinforced concrete is very poor in tension.

    Correct this article….

  33. open-minded August 25, 2009 at 9:25 am

    I don’t understand why the U.S. won’t legalize growing hemp, it’s such an incredibly versatile substance & so easily grown. I don’t think the hemp grown for industrial purposes would be fit to smoke if that’s what people are worried about. On that note, I believe medicinal marijuana should be legalized also.

  34. billster84 August 25, 2009 at 9:06 am

    Yes, but bear in mind, the title is that of, not Tradical Hemcrete. I’ve been to some workshops with it and we have samples all over our office, finished and unfinished and the stuff is awesome. Our friends (Hemp Technologies, LLC) are some of the only ones distributing in the US, their site is

  35. mdandeneau August 25, 2009 at 7:59 am

    What makes me skeptical is that they fail to elaborate on the “7X stronger than concrete claim.” Concrete is much different in terms of compression-bearing loads vs. lateral, that’s why your local strip-mall Tae Kwon Do “expert” can break slats of the stuff but might have a problem putting his foot through a concrete floor. I’d beleive that Hemcrete is stronger laterally but find it very hard to believe it could bear higher compression loads which is basically the only thing non-reinforced concrete is used for anyways.

  36. gerrymetal August 25, 2009 at 7:26 am

    Actually, hemp used to be the most important crop in the US. the first law concerning it was passed by the Virginia assembly in 1619 requiring every household to grow it (see Eric Schlosser, Reefer Madness for historical sources).
    This is the most versatile crop in the WORLD! So, it would be financially plausible due to the crazy number of options open for return on the investment.
    (sorry to nerd it up – 1st post!! :P)

  37. billster84 August 25, 2009 at 7:05 am

    it grows incredibly well in many areas of the US. It’d be great to replace the tobacco farms of NC that have been disappearing for the last couple decades.

  38. Jeff M August 24, 2009 at 10:16 pm


    You clearly have some personal issues to resolve.

    Nevertheless, I agree in that I did not see anything on the Tradical website claiming that Hemcrete is stronger than concrete. The FAQ page states “Hemcrete® is not load-bearing, so the limitation is only on the structural frame.” Additionally, Hemcrete structural blocks compressive strength is stated as 3 MPa, whereas “regular” concrete is in the range of 10-40 MPa.

    I would not be surprised if Hemcrete is 7x stronger in tension, but that doesn’t seem relevant to a comparison of concrete without some explanation. So, this article does appear to be misleading, at best. Please explain, Daniel. Thank you.

  39. dezholling August 24, 2009 at 9:40 pm

    Does anyone know if it would actually become financially plausible if hemp were legal to grow here? Or is that just the hope?

  40. billster84 August 24, 2009 at 9:26 pm

    We are building what we think is the first home in the US using Tradical Hemcrete…and we chose it ourselves :) – not the hemp industry.

    Our team has done a lot (a lot!) of research on it and, since I’ve only been with this group for the past few months, I can’t speak to all of Dead_Unicorns points but I can say that the “doesn’t rot” claim is pretty spot on (lime based binders prevent mold through their pH and by wicking moisture to the outside of the wall where it can evaporate). I can point our engineer or others to this post to answer the rest of your critiques. It is vapor but not water permeable which gives it several advantages over wood in terms of longevity. One other great point is its R-value (measure of thermal resistance used to “rate” insulative performance). Depending on the mix, which influences strength by the way, it can be R-2.5/inch or more. Closed-cell structure of hemp makes it different from other cellulose as well. Really, you can read all about why we like hemp crete in a post we made about our prototype… titled “Why We Like Hemp Crete”

  41. Planner7 August 24, 2009 at 8:32 pm

    Yet another application for hemp (food, fuel, fiber, paper, clothing, medicine, and now building material). This is the replacement for our petroleum economy. We would not have to grow any more cotton, which takes a ridiculous amount of water and pesticide. We could stop chopping down our forests for paper, creating a horrible byproduct in the process of turning wood into paper (not to mention that it lasts longer, and if you don’t believe me, just look at the Declaration of Independence). Now, we can even build with it. Problems aside, you should look at its environmental benefits, as well as the environmental degradation caused by the oil, timber, cotton, and pharmaceutical companies whose processes are just plain nasty! Sometimes the most environmental thing you can do is to keep it simple.

  42. archonic August 24, 2009 at 6:28 pm

    Anyone know if it’s illegal to grow in Canada?

  43. Dead_Unicorns August 24, 2009 at 6:13 pm

    I can’t even enumerate all of the problems with this. But. here is a small list:

    1. Cellulose aggregate concrete(Hemcrete) is NOWHERE near 7 times stronger than stone and sand aggregate concrete. Their claim is a flat out lie! In fact, their website states that the compressive strength is so low that it can’t be used fro load baring applications.

    2. Doesn’t rot is an exaggeration that may be arguable. But, the mold problems with cellulose construction is a very real issue.

    3. Insects, specifically termites are a real issue despite the manufacturer’s claims.

    Cellulose reinforced construction is nothing new. It was used in ancient Egypt and in the Great Wall of China. But, as time and technology advanced, we found better construction materials. The new materials were stronger, cheaper, more durable and easier to manufacture. Not necessarily in that order. Hell there are better cellulose base construction materials already in common use. It’s called wood!

    This is yet another by hemp growers to find a market for their product that nobody seems to want. Whether it’s hemp clothing or construction materials, no one, except for a few Birkenstock wearing granola crunchers is interested in hemp anything.

  44. s3xt0y August 24, 2009 at 4:01 pm

    Wow, thats pretty amazing, doesn’t say how much it is though, or maybe I’m not just looking hard enough.

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