Since there are no currently active contests, we have switched Climate CoLab to read-only mode.
Learn more at
Skip navigation

Please find below the judging results for your proposal.

Finalist Evaluation

Judges'' ratings


Judges'' comments

Congratulations! Your proposal, 3D Printing Hempcrete - The People will know what they want once they see it... in the Buildings contest, has been selected to advance to the Finalists round.

Be proud of your accomplishment – more than 350 proposals were submitted and only a very small number have been advanced through these two rounds of judging.

As a Finalist, your proposal is eligible for the contest’s Judges Choice award, as well as the contest’s Popular Choice award, which is determined by public voting.

If you haven’t already, you will soon receive an email from the Climate CoLab staff with details about the voting period. If you don’t receive that email within the next day, or have other questions, please contact the Climate CoLab staff at

All winners will be announced the week after the voting period ends, on September 12, 2015 at midnight Eastern Time.

Both Judges Choice and Popular Choice will receive a special invitation to attend selected sessions at MIT’s SOLVE conference and present their proposals before key constituents in a workshop the next day, where a $10,000 Grand Prize will be awarded. A few select Climate CoLab winners will join distinguished SOLVE attendees in a highly collaborative problem-solving session. Some contests have additional prizes given by the contest sponsor.

Thank you for your work on this very important issue. We’re proud of your proposal, and we hope that you are too. Again, congratulations!

2015 Climate CoLab Judges

Additional comments from the Judges:

Comment 1:

There are still clear gaps in the proposal. However, the potential of the proposed combination of 3D printing and Hempcrete is worth further exploration and testing. The idea is original and innovative.

Comment 2:

Very interesting proposal with some exciting ideas having significant potential in terms of impact. Although I do not agree with many elements of the proposal (e.g. the idea for the structure), I do appreciate the efforts that the author has put into sharpening the proposal since the last iteration. I think it is conceptually very strong.

Comment 3:

Hemp development is an interesting area within the construction sector with many buildings incorporating hempcrete or similar products. Hemp has been widely used in Europe and supported and subsidised by the EU since the 1970’s. But even with this support it has not become a mainstream product and is still very much seen as a niche environmental and more expensive alternative to traditional construction methods. What I found interesting about this proposal is it pairs high-tech production methods with this local tech raw material. It was interesting to read about the work of Prf. David Mitlin creating a nonmaterial that outperforms graphene from waste hemp – thank you for the link. It would have been great to read more about the proposed process of 3D printing, the proposal is still not clear enough on how this would be integrated into the larger construction sector.

Comment 4:

Project combines 3D Printing with a new material to create an optimized building block, effectively to replace concrete. I am wondering however how durable this is in terms of humidity, moisture etc., also questions of construction and connections to other layers such as insulation, waterproofing etc. arise. Unfortunately this and other physical properties are not described which make it hard to judge feasibility. The connection between the softkill algorithm, the 3d-printing and the material is somewhat unclear, how do they relate to each other and how important are they?. Can this material (fibres) even be 3D printed? When using the ‘bone-like’ structure it is not longer a closed surface but more like a foam, what are the implications on compressive and tensile strength, on thermal resistance etc.? As hempcrete construction is already in place and not novel as such the digital aspects (generative algorithm and 3D printing) seem to make up the innovation part. These however lack a clear description and depth. Biomaterials are most often problematic to scale, and when upscaled they start replacing other crops, causing undesired social and ecological side effects. Given the enormous amounts of concrete and cement used in construction I wonder if ‘hempcrete’, given its technical success, can be more than a niche product.

Semi-Finalist Evaluation

Judges'' ratings


Judges'' comments

Dear author,

We are please to inform you that your proposal is advancing to the next stage.

2015 Climate CoLab Judges.

This proposal features two innovative streams: the development of structural hempcrete and its application to the construction sector through 3D printing. Yet the potential of both is neither fully explored nor are the aims explained. The perspective of spreading pyramidal micro architectures over the country is not the most appealing aspect, as it does not add to the debate on more effective (in terms of S/V ratio, quality and usability of space etc) or affordable building types. It also appears a feature not directly consequent to the use of either the above mentioned technologies. Instead, the highlights of the proposal are a) the structural use of hempcrete (whose hygrothermal characteristics and sequestration potentials have been already confirmed according to the references provided in support of the proposal) that allows to reduce the environmental impact of additional concrete or even timber structures; and b) the possibility of coping this enhanced material with an equally innovative construction technique, 3D printing, which has multiple benefits, from rapid and easy construction, to waste reduction, spatial flexibility and accessibility through open source approaches. The proposal could be reinforced by further developing this synergy and providing details concerning: expected performance of the new material in comparison with the currently available one, environmental and socio-economic advantages of 3D printing versus traditional technologies, application of the material to realise various building components and prefab units (highlighting the positive environmental and socio-economic impact of this construction method). These additions would strengthen this innovative proposal and increase its impact. Given the nature of this proposal, quantitative aspects (such measures of thermal insulation and compressive strength) are equally relevant to understand and appreciate the feasibility of this project and its potential impact. Even though the large scale implementation of this double technological improvement won’t happen in the short term, due to its long term potential impact.

This proposal contains two core ideas- the use of hemp as a bio-based replacement for traditional, more carbon intensive building materials, and the potential for its use in a 3D printing apparatus. As such, both of these ideas are not new by themselves—for example, the Hempcrete house built in North Carolina, which was tangentially referenced in the proposal ( The possibilities exist for both of these ideas to make a difference, and the hurdles are for the most part regulatory. That said, it would have greatly benefited the proposal to focus on either one of those ideas and get into more details regarding the critical details that need to be addressed. The goal of building pyramid shaped designs is not a practical option from either a design perspective or for addressing the housing crisis. While the author references tests that assess the physical properties of hemp-based materials, there is no data provided on any evaluations for the proprietary blend that they have claimed to develop. This is important because you cannot use this material if you are not able to pass basic code requirements on performance. Similarly, is it practical to use this blend for 3D printing? The use of 3D printing in the building industry itself is in infancy, and while there is a burgeoning amount of work being done in this area, there are a lot of challenges to be tackled in using this technology. All said, I think this proposal does merit advancement to the semi-final stage, but the author needs to address the above shortcomings if they are truly interested in pushing the envelope with these ideas.

Share conversation: Share via:

Chad Knutsen

Jul 9, 2015


1 |
Share via:
Thank you everyone for your continuing support and input. I have cleaned up the proposal, adding in more info RE: the process, steps to completion, current status, more references, a few images for clarification of concept etc. I also included more info on the expected performance of the new hempcrete mix I intend to produce. I also took your suggestion to drift away from the pyramidal construction for this proposal. Although there are numerous very interesting benefits to the geometry of a pyramid, energetically and otherwise, it isn't necessarily that relevant to the climate control aims of this contest. So I appreciate you bringing this to my attention. Thank you judges for your time in evaluating and providing feedback for my proposal, it was very helpful in refining this project. I did my best to explain the aspects that were asked about the most, such as the method of construction using smaller 3d printers to create smaller segments to be assembled on site. If there are any further questions or comments, please let me know and I will take them under advisement! Thank you, I look forward to your feedback! Chad K.