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Hempcrete!

c.k.

I missed this forum and I haven’t been here in decades since I’m not really an architect now, but when I’m stumped I know you collectively have the answer, always. So here is it, why is Hempcrete so damn hard to make more mainstream!

 
Oct 26, 23 11:36 pm
Le Courvoisier

Can’t pour concrete stoned

Oct 27, 23 12:18 am  · 
3  · 
natematt

Literally used this joke yesterday, thanks!

Oct 30, 23 2:47 am  · 
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JLC-1

The paper pulp industry and the steel industry may have something to do. Just as bamboo is really hard to introduce into captive markets.



Oct 27, 23 4:42 am  · 
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Janosh

It's a relatively new industry with a lot of supply chain issues. But more generally the US construction market does not give much visibility to low cost high performance materials for the simple reason that there is no large industry to market them and insufficient profit potential for established players to invest. 

Oct 28, 23 10:49 am  · 
2  · 
c.k.

Yes, that’s easy to see even with the most cursory research. I was just wandering if anyone has had any experience or desire to use it in any project. Especially when it comes to building code. 

Oct 28, 23 9:37 pm  · 
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Janosh

​We are using it on a residential project and it has a lot of promise. The building code issue should be trivial if your jurisdiction will accept the use of 2024 IRC Appendix AY in advance of the adoption of the rest of that updated code.

Oct 29, 23 9:50 am  · 
2  · 
natematt

What was the application in that project?

Oct 30, 23 4:13 pm  · 
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Janosh

Hemp-lime nsulation on the exterior side of masonry walls in lieu of rigid board.

Oct 31, 23 12:03 am  · 
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c.k.

that’s amazing to hear! I’d love to hear more on the outcome of that project. And also good to know about the code. I’m just a little bummed that it’s only approved for use in residential projects so far, though that may change.

Oct 29, 23 4:15 pm  · 
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bowling_ball

I've no experience with it and I'm not in the US but can it be used in commercial projects if it's not structural?

Oct 29, 23 5:40 pm  · 
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Janosh

Yes

Oct 31, 23 10:34 am  · 
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c.k.

yes it’s not structural, it’s infill material, but that is the case with many other materials. The issue is rather the fact that you’re constrained to using a wood frame structure with it rather than a metallic frame since it would corrode the metal.

Oct 29, 23 6:59 pm  · 
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Before products like this can be used structurally, there needs to be testing of the product so there is solid understanding of structural properties.

Oct 30, 23 4:25 am  · 
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natematt

CK, this was my understanding, for most applications in which we use concrete, It's not even a closely comparable product.

To RBs point... I'm pretty sure it's been tested and it's just not that good. you can't get 3000psi hempcrete, etc, etc, etc.

Oct 30, 23 4:16 pm  · 
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Janosh

All of this is address in the Appendix which can easily be found with a google search, but yes, Hempcrete (technically "Hemp Lime" is explicitly an insulation material and while it is required to have a minimum compressive strength that is just for use as a plaster substrate. It may be used in buildings of any construction type or material, however the code contains provisions that need to be satisfied when it is applied in contact with adjacent to non-stainless metallic materials.

Oct 30, 23 5:40 pm  · 
1  · 

First, there's this thing called investors and there is that other thing..... federal laws criminalizing cannabis and help has been classified as cannabis. Until the spectre of FBI and DEA knocking down your door shock and awe style and handcuffing you and physically throwing you into the back of law enforcement vehicle taking you directly to jail. Manufacturing a product like this needs interstate commerce and even international. The problem in the U.S. is interstate commerce is what gets you on the FBI, DOJ, and DEA radar and their jurisdiction. The supply chain issue is getting everything needed to produce the concrete from hemp plant farm to hempcrete product, all without crossing state borders, transportation on any federal/interstate highway, etc. When any of these occur, you may be under criminal investigation. Even though many states have done some form of legalizing. The problem is even if each state from San Diego to Canadian Border, is legalized, the feds will be watching  hawks for any point where it becomes a federal nexus. If the road goes through a National Park, you're busted. 

You can see the concern of literally going to prison for 20+ years is seriously concerning and criminal liability concerns investors of FBI/DEA/DOJ coming in shock and awe and literally arresting the investors and taking their computers in what is a search & seizure and arrest warrant. Even though hemp doesn't have the same issues as THC as regular ol' marijuana, it still has legal issues. 

Until hemp is absolutely and completely decriminalized and removed from the federal restrictions, ENTIRELY, and marijuana being de-criminalized but of limited controlled substance similar to tobacco and alcohol in terms of controlled substance.... on the federal level.... it is pretty much an issue that limits hempcrete getting major adoption. 


Oct 30, 23 4:23 am  · 
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natematt

Refer to the comments above. I’m pretty sure this relatively little to do with the legality of hemp issue, and much more to do with the product just not being a suitable replacement for concrete in most applications. However, supply chain generically does have a big impact on concrete mix designs, so there is some accuracy to that.

Oct 30, 23 4:23 pm  · 
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I think it is all the above. It is not a disagreement with what has been said. It is a combination of issues. You have the legal issues. While I agree that some hemp products are not suitable replacement for concrete. Then there is also products that might. It might effect things like geometry of the foundation and such. There is a number of hybrid options. The thing is help is a fiber material that provides potential tensile properties that can be used in lieu of steel reinforcement which is why help is proposed. For low-rise buildings, this probably not a major issue. However, the lack of testing data for a new product has an impact on regulatory approval. To support manufacturing hempcrete, you aren't going to have a complete process of hemp farm through every processing stage leading to making of the hemp for hempcrete with a few large-scale hempcrete manufacturing with hemp from multiple states to any one of maybe a handful of factories. You won't be having a factory in every state. Right now with federal law, you have to replicate every facility from farm to hempcrete factory in every single state including warehousing and shipping so nowhere does any of this stuff travel on interstate highways crossing any state boundary line even once. Once that happens, you have the concern of the feds in their shock and awe shutting down and arresting the entire factory and everyone associated like the biggest drug bust in the U.S. like if you are a Columbian drug lord. We need to actually fully remove hemp from this kind of Federal oversight. Those investors / venture capitalists aren't going to invest millions or even billions of dollars into something (even advancing R&D in making a better hempcrete product suitable for structural and the various laboratory testing to support it), if there is the specter of the law coming in arresting them, seizing their computers, arresting everyone in the process under a big ass RICO investigation with massive scale indictments. This is something that would greatly keep investment capital away. Adoption by architects are concerned about other matters, obviously, like you said. As I said, it isn't a single issue and I'm pointing to other factors than just reiterating what has been said, entirely like why there may be investors hesitant in investing capital because that investment can lead to advancing hempcrete, potentially leading to a hempcrete product that would be suitable for structural. I wouldn't say it will be applicable to every structural application. I probably wouldn't consider it for structural in high-rise / skyscaper application. At least not yet. Can it be adequate for low-rise. I think it might be possible. Low-rises as in 1-3 stories, roughly. I can see it having potential with enough research in the process.

Oct 30, 23 5:08 pm  · 
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TLDR? Ok, short version, I agree with the above. It is just an added angle of view on the issue. It is a combination of these issues. What issue is the strongest factor depends on the individual and what issues are strongest factors to their decision making. Investors will be concerned with their investment not being busted and shutdown by some aggressive law enforcement. Makes sense. Would you? Other factors is good product for the right application. It can all be marketed but how depends on best uses. Making money is making money. Law enforcement shutting you down is a major money loss. For architects and engineers, I see the structural properties matter more to them than some law enforcement officer busting down your office doors with guns and roughly arresting them. and throwing them in the back of the fed's squad cars. You get the idea.

Oct 30, 23 5:15 pm  · 
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c.k.

Maybe Hempcrete was a very bad marketing idea, as a name. In truth nobody expects it to behave anything like concrete, and the similarity ends with the fact that you can cast it in place, using movable form work.  
But really, who cares about compression when it does everything else? Moisture regulating, insulation, fireproof, rot proof and pest proof. If you look at how the wall section is simplified, there’s something really appealing about how it performs.

And the cultivation issue and federal laws conflicting with state laws is absolutely true. Any farmer who wants to grow it cannot borrow money from a bank in a normal way and even if they do everything right, if cross pollination with high THC plants (industrial hemp permits are contingent on thc levels below 0.3) can have severe consequences.

This is very informative on all these issues, but also, on why it’s worth it.

https://healthymaterialslab.org/tool-guides/hemp-lime-1

Oct 30, 23 10:06 pm  · 
2  · 

On a related note there is an event next week

 "Organized in partnership with Healthy Materials Lab at Parsons School of Design, this program convenes critical voices from across the hemp ecosystem to investigate how new design approaches and building with hemp can be a viable, healthy alternative for design and construction in the United States."

https://archinect.com/schools/bustler-event/150173385/from-field-to-form-hemp/14093

Oct 30, 23 11:13 pm  · 
1  · 
c.k.

you can tell I’m a convert because I already got my ticket to that!

Oct 30, 23 11:44 pm  · 
1  · 
c.k.

dang I can’t seem to get a handle on this reply feature

Oct 30, 23 11:44 pm  · 
1  · 
Wood Guy

One problem is that there are several different construction techniques or products that fall under the "hempcrete" umbrella. The more traditional methods are very labor-intensive and prone to mold if not done properly, but perform very well when they are done properly. A friend of mine wrote one of the bibles on it: https://www.amazon.com/Essenti....

There are also premade bricks, premade blocks, sprayed systems, batt systems, and probably others I'm not thinking of. All can work well in the right context but few people are familiar with them. Hopefully that changes but I'm not holding my breath.

Oct 31, 23 4:42 pm  · 
1  · 

Thank You for chiming in on this. I agree, don't hold your breath. We operate at the speed of molasses in Antarctica winter, too much so... as a profession. In any case, I think it would be good for the profession to become more familiar with the stuff even if they don't use the stuff in projects. Hard to do without using the products in projects but worth knowing about on a level to be able to make informed decisions about it in projects.

Oct 31, 23 5:44 pm  · 
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