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Building with Mycotecture: Deep Dive into Fungal Solutions for Sustainable Architecture

Updated: Jun 12

Mycotecture can be defined as the use of fungal organisms to shape the built environment. This usually involves leveraging the growth of fungal mycelium, (or the root-like branching hyphae of the organism), to mold into products that are useful for form-making, insulation, or surface definition. In 2009 an artist named Phil Ross made an exhibit in a Dusseldorf gallery called the “Tea House” where he stacked living blocks of mycelium/wood composites into an arch. It was called the Tea House because the blocks were growing reishi mushrooms which were harvestable allowing one to make tea there in the gallery from the mushrooms. Ross has gone on to co-found the hugely successful MycoWorks company that makes high end mycelium leather. In 2014 architect David Benjamin won the Young Architects Program competition at MoMA’s PS1 gallery in Queens, New York. With Ecovative Design, the other hugely successful mycelium materials company, Benjamin built the HiFi tower as a temporary exhibit in the PS1 courtyard. One criterion for the competition is that the materials were to be compostable/biodegradable at the end of the summer making Ecovative’s mycelium bricks ideal.


Figure 1: Left the Tea House aka Mycotecture Alpha 1 by Phil Ross, Dusseldorf, 2009, Right: the HiFi by David Benjamin and Ecovative Design, New York, 2014. Image credits Forbes and ArchDaily.

 

That works for temporary exhibits but what about buildings? Isn’t it bad if building materials are compostable? Yes and no. You certainly wouldn’t want any of your building materials to breakdown when you need them, but on the other hand 600 million tons of construction and demolition (C&D) waste end up in landfills in the US each year.[1] Many of those materials were compostable in their raw state but have been mixed with chemicals that are dangerous or toxic so they cannot be used as compost. They instead rot in landfills where they create greenhouse gasses and poison the earth.[2] We build with wood all the time and wood is biodegradable. But when protected from the elements, wood can last a very long time. Many of us live in wooden houses that are over a hundred years old, there are cathedral trusses that are many centuries old, and there are timber lintels and shoring in pyramids from ancient Egypt that are thousands of years old.[3] Good architects, even ancient architects, know that biogenic materials can last forever if they are protected from the elements.

 


Figure 2: From left to right: Photo of The Bent Pyramid of Dasher (credit: Monnier), Axonometric of pyramid showing inner chamber, Detail drawing of inner chamber, Photo showing wood formwork members originally placed circa 2400BCE (credit: Valeriy Senmuth Androsov.) Taken from Monnier, Franck & Puchkov,[4]

Until recently, mycelium materials have not been used in load bearing construction. That changed in 2023 when MycoHab, a startup founded by researchers at redhouse studio and MIT, and funded by Standard Bank, built the first self-supporting structure from the byproduct of mushroom cultivation, i.e. mycelium materials (www.myohab.com). MycoHab started with a question, can southern Africa’s bush encroachment problem be turned into food and housing? The answer is yes, and the processes, if proliferated, could combat desertification, climate change, and hunger.

 


Figure 3: Left Photo of MycoHab 1.0, the first self-supporting mycelium materials building completed in Windhoek, Namibia in 2023. Right: Exploded Axonometic view of the building that shows the structural block walls.


The Substrate: turning waste into opportunity


Bush encroachment in Namibia, where MycoHab operates, represents 450M tons of biomass that should be extracted every 15 years to fight desertification.[5] The bush has been growing out of control when modern “land management” practices changed the mostly wild territories into cattle ranches and other private properties. This changed the grasslands to bushlands, and the bush is soaking up what little water Namibia receives. The Namibian Ministry of Agriculture, Water and Land Reform MAWLR, and the Namibian Biomass Industry Group N-BIG are looking for uses for this bush to aid in their bush-thinning program. A 2023 report shows that most companies would just like to burn it, in the form of charcoal or wood pellets.[6] Another report prepared for the German international aid organization Deutsche Gesellschaft für Internationale Zusammenarbeit, or GIZ, looked at the best practices as it pertains to the environment and recommended the creation of biochar to be used for soil amendments, and mycotecture ala MycoHab as the processes that can store carbon dioxide long term. [7]

 

Southern Africa is not alone in having biogenic waste resources that go underutilized. Bagasse is the waste from sugarcane farming and over one billion tons of it is produced each year. [8] Much of it is burned releasing many different greenhouse gases, volatile organic compounds, and, in some cases, heavy metals like arsenic and mercury. [9] All grain production has the byproduct of straw. For just wheat alone 529 million tons of straw are produced annually.[10] This is not hay and does not have any nutritional value to animals. It does, however, have value to fungi and can be used as a substrate for mushroom cultivation and building material production.


Figure 4: MycoHab interior. Blocks are left exposed on the interior and give a warm natural feeling. The mycoblocks for all of the bearing walls and act as insulation as well as structure.

The MycoHab process


Bush is harvested in alignment with MAWLR and N-BIG recommendations for thinning but leaving an appropriate amount to allow grassland to reestablish. The bush is hammermilled into 1-3mm chips. The chips are delivered to site, are mixed with water and a small amount of bran (5% by weight), and put into cultivation bags. The bags are put into a steamer that pasteurizes the wet woody materials. They are then let to cool in a laboratory before being inoculated with mycelium the following day.


Inoculation is done in the lab under laminar flow hoods that blows HEPA filtered air keeping the area as clean as possible. This restricts competitor organisms from also inoculating the substrates.  The inoculant is grain spawn: P. ostreatus (HK35) wheat grain by Sylvan Africa at 5% by weight. The bags are sealed, mixed thoroughly, and put into incubation rooms. This is a process any cultivator would know well.

 

From here we wait. It takes 30+1 days to make a mycoblock. 30 days for the harvest of mushrooms and one day extra to make the block. 31 days may seem like a long time to make a block but it’s a very short time to get a full harvest and a block. The mushrooms are easily harvested from the outside of the bags or growth container and the left-over material, or mycelium by-product is used to make the blocks.

 


Figure 5: From left to right. Namibian encroacher bush: Acacia mellifera, oyster mushrooms growing from a column of bush dust fused with mycelium, Harvested mushrooms that go to market, the mycelium/bush composite by-product isolated, this is put into a 200 ton horizontal press, The resulting MycoBlock after pressing and baking.  

Mycelium waste, also referred to as spent mushroom substrate (SMS), is the lignocellulosic by-product of mushroom cultivation.[11] The waste contains a network of hyphae surrounding lignocellulosic substrate particles which have been partially decomposed by the fungi. When compacted and baked the composite is left with the “best of both kingdoms”, the liberated Plantae cellulose separated from the lignin bonds, now fused together by the chitin-rich mycelium from Fungi at a cellular level.


Material Characterization


These materials are designed to be used in compression and must by laterally stabilized by forming a bond between the masonry units that enables the solid wall to act as shear wall. As these materials perform like solid wood, they can be glued together using standard wood glue. Eco-friendly wood glue is mixed bush substrate to make a mortar that fuses the blocks together. The compression strengths were tested at Namibian Technical Services NTS, an independent testing laboratory.


Figure 6: Chart showing Modulus of elasticity and compression results from multiple tests. MOE average was 37MPa with standard deviation of 17. Compression Strength was 6MPa with standard deviation of 0.66 and minimum of 5.3MPa.

The results far exceed the standard for a single-story building in Namibia (3MPa) at 6MPa. This is similar to concrete masonry units, aka CMUs, aka concrete blocks in this region. CMUs are hollow core building units that are fused together with mortar. The cores are sometimes filled with reinforcing steel and mortar as they are not very laterally stable otherwise. The chart in Figure 6 shows the compression strength and modulus of elasticity results from several tests done at Namibia Technical Services. The highest and lowest results were removed and the averages and standard deviations were recorded. The average compression strength was 6MPa, with a low of 5.3MPa and a high of 6.8MPa and a standard deviation of 0.66. The average MOE value was 37MPa, with a high of 62MPa, a low of 15MPa, and a standard deviation of 17. Similar materials made in Cleveland by MycoHab founding partner redhouse studio have had compression strengths of 26MPa and MOE values as high as 207MPa.[12] These results indicate that is room for improvement in strength and consistency, but they represent a good start to proving the capability of converting waste biomass into food and housing. Watch a mycelium block vs conrecete brick comparison video here.

 

Carbon accounting


Mycoblocks are composed of 42.9% organic carbon[13], a carbon dioxide equivalent (CO2e) of about 20.5 kg per 13.0 kg of mycoblock, according to the following equation. 

Therefore, 1.58 kg CO2e is stored in each kilogram of block produced.  With carbon accounting, we can’t stop there, however. This is the carbon dioxide that is stored long term in the mycoblock that will be prevented from reentering the atmosphere through composting away, but we must add (or subtract) the carbon emissions from the manufacturing that enabled us to lock the CO2 away. We must include the emissions for the baking which, unfortunately, uses diesel, the electricity to run the site, the transport of raw materials and other factors shown in Table 1.

Emissions (kgCO2/block)

 

Biomass Sequestration

-20.5

Biomass Regrowth

-11.2

Diesel

+8.68

Electricity

+5.02

Mushroom Transport

+2.4

Mushroom Packaging

+2.01

Bush Harvesting

+0.2

Biomass Transport

+0.12

Total

-13.27

Table 1: Emission shown as positive numbers and sequestration shown as negative numbers

So, the above calculation of 20.5 kg of CO2e stored per 13kg block is reduced to 13kg of CO2e stored per 13 kg block. This means for every kilogram, pound, ton, or name your unit, the equivalent amount of carbon dioxide is kept from the atmosphere for the life of the building.


Compare this to concrete. In 2022 nearly four billion (metric) tons of concrete was made globally which produced 8% of the 50.6 gigatons (giga means billion) of CO2e, or four gigatons.[14] [15] [16]   That is a ton of carbon dioxide equivalent for every ton of concrete produced. Imagine erasing the 4Gt of concrete emissions and replacing it with 4Gt of carbon sequestration, it would reduce global emissions by 16%. Mycoterials will probably never replace concrete in substructures, but maybe one day replace concrete in superstructures.

 

Imagine a scenario where mycoterials are developed to the capacity of cross laminated timber, aka Mass timber, aka CLT. CLT is made be laminating small pieces of lumber together to make slabs and columns that erect quickly. It is being touted as an environmentally friendly alternative to concrete and steel construction because the biogenic timber stores CO2, and is currently allowed in high-rise construction in many parts of the world including the US. While a huge improvement to concrete, as this building practice proliferates, we’re likely to see an increase in deforestation. Where will all the lumber come from? This is where the circularity of mycoterials comes into play. Fungi are famous for turning waste materials into useful, and often delicious goods. This can be leveraged in mycotecture effectively. MycoHab turns unwanted bush into food and housing. Another redhouse project, biocycler, uses fungi to remediate and recycle construction and demolition (C&D) waste with the goal of recycling entire houses and creating environmental justice. MycoCycle is another such company looking converting C&D into useful materials. In space there is no biomass to convert into fungal materials but there is radiation and NASA is looking at ways to grow buildings off-planet using mycotecture that can leverage dangerous space radiation as a resource.



 

Contributing Author: Christopher Maurer


Christopher Maurer is an architect and inventor of bioterial technologies. Chris has developed new architecture and manufacturing processes for NASA, MIT and other major research institutions. He has designed and built all over the world and is committed to furthering regenerative architecture to help humanity and ecosystems recover from current modes of building and production.


 

References


[1] US Environmental Protection Agency:  https://www.epa.gov/

[2] Molla A, Tang P, Sher W, Bekele D, Chemicals of concern in construction and demolition waste fine residues: A systematic literature review, Journal of Environmental Management, Volume 299, 2021, 113654, ISSN 0301-4797,

[3] Monnier, Franck & Puchkov, Alexander. (2016). The construction phases of the Bent Pyramid at Dahshur. A reassessment. ENiM. 9.

[4] Ibid.

[5] Lindeque C, Stoldt M & Perche J, Harvesting and Processing Namibian Encroacher Bush Vol.2, Namibia, 2023.

[6] Ibid

[7] Lindeque C, Kirksmith C, Gao Y, Maurer C, Mershin A. Analysis of Potential Payment Schemes for Ecosystem Services in the Namibian Biomass Sector. Bush Control and Biomass Utilization (BCBU). Windhoek, 2022.

[8] Pula, Bhargavi & Ramesh, Shradha & Pamidipati, Sirisha & Doddipatla, Purnima. (2021). A comparative study of greener alternatives for nanocellulose production from sugarcane bagasse. Bioresources and Bioprocessing. 8. 10.1186/s40643-021-00477-0.

[9] M.A.M. Costa, N.C.B. Schiavon, M.P. Felizardo, A.J.D. Souza, K.J. Dussán, Emission analysis of sugarcane bagasse combustion in a burner pilot, Sustainable Chemistry and Pharmacy, Volume 32, 2023, 101028,

[10] Tufail T, Saeed F, Afzaal M, Ain HBU, Gilani SA, Hussain M, Anjum FM. Wheat straw: A natural remedy against different maladies. Food Sci Nutr. 2021 Feb 27;9(4):2335-2344. doi: 10.1002/fsn3.2030. PMID: 33841849; PMCID: PMC8020915.

[11] Lesa KN, Khandaker MU, Mohammad Rashed Iqbal F, Sharma R, Islam F, Mitra S, et al. Nutritional Value, Medicinal Importance, and Health-Promoting Effects of Dietary Mushroom (Pleurotus ostreatus). Journal of Food Quality [Internet]. 2022 Aug 27;2022:e2454180.

[12] Brandić Lipińska M, Maurer C, Cadogan D, Head J, Dade-Robertson M, Paulino-Lima IG, et al. Biological growth as an alternative approach to on and off-Earth construction. Frontiers in Built Environment. 2022 Sep 19;8.

[13] To determine the quantity of carbon dioxide sequestered in the mycoblocks, elemental analysis (GLI Procedure ME-14) was performed by Galbraith Laboratories, Inc (Knoxville, Tennessee).  https://galbraith.com/services/elemental-testing/

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