*2.1. Parametric Design for Serpentine Walls*

(**a**) (**b**)

*2.2. Summary of Myco-Fabrication Methods* 

schemes and to estimate material volume requirements.

*2.1. Parametric Design for Serpentine Walls*  To facilitate the generation of an expansive and diverse family of undulating wall To facilitate the generation of an expansive and diverse family of undulating wall geometries, a custom computational design script was developed in Rhino/Grasshopper [57].

sions, including the generation of digital fabrication protocols for making the formworks. First, a curve was generated using design variables that included the number of control points that composed a V or U-shaped "unit", the length and width of the unit, whether the curve was generated with poly-lines or poly-curves, and how many units composed the length of the curve. Figure 6a shows three examples of such basic walls in top view. Next, the underlying three-dimensional geometries of the wall units were represented as a planer ruled surface. The geometries used for the two prototypes were generated from the base curve and its mirror, according to a specified height. The final design stages consisted of a set of thickening and geometrical extraction protocols (Figure 6b) that helped generate the formwork schema specific to the myco-fabrication technique being tested.

**Figure 6.** (**a**) Examples of poly-line- and poly-curve-based periodic curves generated with the parametric design script for designing serpentine walls; (**b**) three-dimensional extractions and transformations afforded by the script. Vertical slicing and thickening were both used to design formwork

The experimental structures grown for the biomaterial building exposition tested

myco-welding and fabric-forming techniques for growing large monolithic blocks and assembling them into efficiently formed wall structures. Due to their inherent lightness, assemblies of large elements were not only possible, but also offered potential advantages

geometries, a custom computational design script was developed in Rhino/Grasshopper

The script generated a range of three-dimensional forms for serpentine walls. The geometries were generated from a periodic base curve that informed later design decisions, including the generation of digital fabrication protocols for making the formworks. First, a curve was generated using design variables that included the number of control points that composed a V or U-shaped "unit", the length and width of the unit, whether the curve was generated with poly-lines or poly-curves, and how many units composed the length of the curve. Figure 6a shows three examples of such basic walls in top view. Next, the underlying three-dimensional geometries of the wall units were represented as a planer ruled surface. The geometries used for the two prototypes were generated from the base curve and its mirror, according to a specified height. The final design stages consisted of a set of thickening and geometrical extraction protocols (Figure 6b) that helped generate the formwork schema specific to the myco-fabrication technique being tested. geometries were generated from a periodic base curve that informed later design decisions, including the generation of digital fabrication protocols for making the formworks. First, a curve was generated using design variables that included the number of control points that composed a V or U-shaped "unit", the length and width of the unit, whether the curve was generated with poly-lines or poly-curves, and how many units composed the length of the curve. Figure 6a shows three examples of such basic walls in top view. Next, the underlying three-dimensional geometries of the wall units were represented as a planer ruled surface. The geometries used for the two prototypes were generated from the base curve and its mirror, according to a specified height. The final design stages consisted of a set of thickening and geometrical extraction protocols (Figure 6b) that helped generate the formwork schema specific to the myco-fabrication technique being tested.

To facilitate the generation of an expansive and diverse family of undulating wall geometries, a custom computational design script was developed in Rhino/Grasshopper [57]. The script generated a range of three-dimensional forms for serpentine walls. The

**Figure 5.** Serpentine walls designed by Thomas Jefferson and built by slave labor that enclose the gardens at the rear of the residences of the historical academical village at the University of Virginia

*Biomimetics* **2022**, *7*, 129 9 of 23

located in Charlottesville, VA, USA. Photos by the author.

*2.1. Parametric Design for Serpentine Walls* 

**Figure 6.** (**a**) Examples of poly-line- and poly-curve-based periodic curves generated with the parametric design script for designing serpentine walls; (**b**) three-dimensional extractions and transformations afforded by the script. Vertical slicing and thickening were both used to design formwork schemes and to estimate material volume requirements. **Figure 6.** (**a**) Examples of poly-line- and poly-curve-based periodic curves generated with the parametric design script for designing serpentine walls; (**b**) three-dimensional extractions and transformations afforded by the script. Vertical slicing and thickening were both used to design formwork schemes and to estimate material volume requirements.

### *2.2. Summary of Myco-Fabrication Methods 2.2. Summary of Myco-Fabrication Methods*

The experimental structures grown for the biomaterial building exposition tested myco-welding and fabric-forming techniques for growing large monolithic blocks and assembling them into efficiently formed wall structures. Due to their inherent lightness, assemblies of large elements were not only possible, but also offered potential advantages The experimental structures grown for the biomaterial building exposition tested mycowelding and fabric-forming techniques for growing large monolithic blocks and assembling them into efficiently formed wall structures. Due to their inherent lightness, assemblies of large elements were not only possible, but also offered potential advantages over other previously demonstrated methods of building with myco-materials. Taking inspiration from pre-cast concrete traditions, the goal for both prototypes was to demonstrate re-usable formwork systems that produced large myco-material building components offsite in semi-controlled working conditions. The strategies intended to reduce the demand of long labor hours, reduce the risk of contaminating large colonies of myco-materials, and reduce uncertainty during on-site assembly. Numerous practical and contextual considerations had to be determined, which ultimately influenced the specific designs and techniques used to complete them. These considerations included if the structure was going to be exhibited indoors or outdoors, the location the structure's parts were going to be grown, the materials and fabrication resources on-hand for fabricating the formwork, how many students were available to contribute to the project, and if the author would be present for the various stages of growing and assembly. While the two structures shared a common underlying formal logic for undulating "serpentine" walls, the formal character and complexity of each serpentine wall prototype was intimately related to its respective method of mycofabrication. The two structures were grown in two different geographic locations in the United States. At their core, these were academic projects, whereby the complexities in the form and technique had to remain accessible to UVA and K-State students both at undergraduate and graduate levels.

### 2.2.1. Myco-Welding Slabs into Monolithic Building Units

The structure exhibited outdoors on the grounds was intended to be cultivated and assembled locally by UVA students. As such, the scale of the structure, the complexity of its form, and the accessibility of the fabrication and growing techniques were precisely selected. As a base technique, myco-welding offered numerous advantages that better aligned with the number of students involved and how much time they could contribute. In devising the proposed methodology, a driving consideration was that most of the physical effort was during a week-long workshop with participating UVA students with design and engineering backgrounds. Myco-welding was advantageous in this context because the two phases of growth de-concentrated continuous labor hours needed for large in situ monolithic mycelium casting techniques.

The prototype wall structure, later named La Parete Fungina, was created from two wall units, each built from seventeen V-shaped slabs myco-welded into three "chunks". Nine different V-shaped formworks were needed (Figure 7a). Noting the labeling scheme in the figure, the palindromic sequence <a, b, c, d, e, f, g, h, i, h, g, f, e, d, c, b, a> described a complete wall unit, with eight of the forms being repeated in each unit. The formworks were intended to function as re-usable slip-molds to address the ethical dilemma of plastic or other non-cellulosic material being ubiquitously used in the production of myco-material objects. These formworks were intended to be simple to make, and because they had very limited contact with growing materials, they could be created from wood and fabricated with basic tools. For assembly on-site, a friction-based connection system (Figure 7b) was developed, so the structure could easily be disassembled when the Exposition was taken down. A unique byproduct of prolonged growth inherent to myco-welding was that it produced overgrowth: a thick layer of pure mycelium grew on the surfaces of the units. The overgrowth was like a layer of hydrophobic defense for the fungal colony, both while it was alive and after being dried and immobilized. Having such a performative benefit meant that myco-welding was the logical choice for a structure being exhibited outdoors. *Biomimetics* **2022**, *7*, 129 11 of 23

**Figure 7.** Design diagrams for La Parete Fungina. (**a**) Diagram of the nine different wooden slipform frames (a–i) designed for growing slabs; (**b**) axonometric assembly diagram of the unit chunks highlighting the friction-based connection system of the wooden stakes. Drawings by Emmett **Figure 7.** Design diagrams for La Parete Fungina. (**a**) Diagram of the nine different wooden slip-form frames (a–i) designed for growing slabs; (**b**) axonometric assembly diagram of the unit chunks highlighting the friction-based connection system of the wooden stakes. Drawings by Emmett Lockridge.

### Lockridge. 2.2.2. Fabric-Forming Monolithic Units

2.2.2. Fabric-Forming Monolithic Units The structure exhibited indoors in the UVA's School of Architecture gallery was The structure exhibited indoors in the UVA's School of Architecture gallery was grown in spring 2022 at K-State in the context of a research seminar instructed by the author

grown in spring 2022 at K-State in the context of a research seminar instructed by the author on myco-materials and myco-fabrication. In the introduction of the course, the

were challenged to work collaboratively and contribute efforts toward an alternative expression of myco-fabrication. In contrast to the structure being grown at the UVA, the prototype later named L'Orso Fungino leveraged the lightweight properties of myco-materials using large monolithic elements that were cast in re-usable wood and fabric formwork. The complexity and fabrication methods chosen were tuned to the available resources, the skill levels of the students involved, and the short 6-week timeline for all the design and production. In situ monolithic mycelium casting techniques were deemed advantageous, because most of the physical effort available from participating students and research assistants in the lab was during a weekly four-hour session. The custom formwork apparatus for growing the wall units (Figure 8a) was designed to be quickly assembled, collapsible, and re-usable. Vertical perforated cardboard tubes were grown into the matrix of the units to provide air into the thickest parts of the colony during growth and to later serve as a conduit for a post-tension connection system (Figure 8b). The top and bottom surfaces of each unit were detailed such that there were interlocking adjacencies between the two units, the top compression plates, and the base. Due to the anticipated lightness of each unit, a post-tensioning system was a key feature of this prototype. It was hypothesized that loading the units in compression with cables running through the card-

board tubes would bring additional strength and stability to the assembly.

on myco-materials and myco-fabrication. In the introduction of the course, the graduate architecture students were immersed into the question of myco-fabrication techniques for large monolithic blocks assembled into efficiently formed wall structures. They were challenged to work collaboratively and contribute efforts toward an alternative expression of myco-fabrication. In contrast to the structure being grown at the UVA, the prototype later named L'Orso Fungino leveraged the lightweight properties of myco-materials using large monolithic elements that were cast in re-usable wood and fabric formwork. The complexity and fabrication methods chosen were tuned to the available resources, the skill levels of the students involved, and the short 6-week timeline for all the design and production. In situ monolithic mycelium casting techniques were deemed advantageous, because most of the physical effort available from participating students and research assistants in the lab was during a weekly four-hour session. The custom formwork apparatus for growing the wall units (Figure 8a) was designed to be quickly assembled, collapsible, and re-usable. Vertical perforated cardboard tubes were grown into the matrix of the units to provide air into the thickest parts of the colony during growth and to later serve as a conduit for a post-tension connection system (Figure 8b). The top and bottom surfaces of each unit were detailed such that there were interlocking adjacencies between the two units, the top compression plates, and the base. Due to the anticipated lightness of each unit, a post-tensioning system was a key feature of this prototype. It was hypothesized that loading the units in compression with cables running through the cardboard tubes would bring additional strength and stability to the assembly. *Biomimetics* **2022**, *7*, 129 12 of 23

**Figure 8.** Design diagrams for L'Orso Funigno. (**a**) Exploded axonometric diagram of the formwork apparatus created to grow the monolithic wall units; (**b**) axonometric diagram of the monolithic wall units highlighting the post-tension system that applied a compressive force on the units with a mechanically tightened cable between plywood base and top plate. Drawings by Emmett Lockridge. **Figure 8.** Design diagrams for L'Orso Funigno. (**a**) Exploded axonometric diagram of the formwork apparatus created to grow the monolithic wall units; (**b**) axonometric diagram of the monolithic wall units highlighting the post-tension system that applied a compressive force on the units with a mechanically tightened cable between plywood base and top plate. Drawings by Emmett Lockridge.

### *2.3. Materials*

*2.3. Materials*  The myco-materials used for both prototypes presented below were procured from Ecovative [13] and paid for with funds provided by the exposition. Within the budget, each prototype structure could be grown from at most one pallet of myco-materials, weighing roughly 325 kg. For these prototypes, one pallet held sixty-five 5 kg bags or 0.6 cubic meters in total volume of wet living material. Ecovative's patented material was a The myco-materials used for both prototypes presented below were procured from Ecovative [13] and paid for with funds provided by the exposition. Within the budget, each prototype structure could be grown from at most one pallet of myco-materials, weighing roughly 325 kg. For these prototypes, one pallet held sixty-five 5 kg bags or 0.6 cubic meters in total volume of wet living material. Ecovative's patented material was a hemp substrate

hemp substrate inoculated with a fungus from the phylum Basidiomycota, whose fruiting

to be kept at approximately 4 °C to prevent the fungi from growing too quickly and fully consuming the substrate. Ideally, they should have been freight-shipped in refrigerated containers and if proper refrigerated storage was not available, immediately processed and packed into formworks. If kept unrefrigerated, the material would grow into a hardened mass in the bags within 3 to 4 days, making it labor- and time-intensive to break the hemp fibers apart. The structures grown at the UVA and K-State were grown in schools

Each structure tested assembly strategies for growing large mycelium building units and assembling them into prototypes of efficiently formed serpentine wall prototypes. As a pair, they demonstrated the flexibility and facility of myco-materials to adapt to different approaches of fabrication based on the available tools, materials, and knowledge. La Parete Fungina demonstrated two undulating wall units standing side-by-side, each created from seventeen myco-welded slabs. L'Orso Fungino revisited the in-situ monolithic fabric forming of units that were repeated, stacked, and post-tensioned. While developing the two techniques, a major concern was to design the formwork systems to be re-usable.

of architecture, which did not have access to large-scale refrigeration.

**3. Results and Discussion: Two Serpentine Wall Prototypes** 

bodies resembled the brackets produced by reishi.

inoculated with a fungus from the phylum Basidiomycota, whose fruiting bodies resembled the brackets produced by reishi.

The storage of these materials could have been a major challenge, because they had to be kept at approximately 4 ◦C to prevent the fungi from growing too quickly and fully consuming the substrate. Ideally, they should have been freight-shipped in refrigerated containers and if proper refrigerated storage was not available, immediately processed and packed into formworks. If kept unrefrigerated, the material would grow into a hardened mass in the bags within 3 to 4 days, making it labor- and time-intensive to break the hemp fibers apart. The structures grown at the UVA and K-State were grown in schools of architecture, which did not have access to large-scale refrigeration.

### **3. Results and Discussion: Two Serpentine Wall Prototypes**

Each structure tested assembly strategies for growing large mycelium building units and assembling them into prototypes of efficiently formed serpentine wall prototypes. As a pair, they demonstrated the flexibility and facility of myco-materials to adapt to different approaches of fabrication based on the available tools, materials, and knowledge. La Parete Fungina demonstrated two undulating wall units standing side-by-side, each created from seventeen myco-welded slabs. L'Orso Fungino revisited the in-situ monolithic fabric forming of units that were repeated, stacked, and post-tensioned. While developing the two techniques, a major concern was to design the formwork systems to be re-usable. Consequently, the formal character and complexity of each structure were intimately related to their respective method of myco-fabrication. Both were assumed to be compressionbearing structures, even if they were not exhibited resisting external loads.

### *3.1. La Parete Fungina*

For the structure grown by UVA students, pre-emptive planning took place two weeks before the workshop in January 2022. This included the development of the script described above in Section 2.1, hiring and coordinating with a research assistant at the UVA, and purchasing materials for the formwork. The five-day workshop was attended by undergraduate students from both engineering and design backgrounds during daily fourhour sessions. For the first three days of the workshop, the primary goals were fabricating the wooden formwork and creating a growing cart. Nine wooden formworks (Figure 9a) were hand-built from 17 mm unfinished whitewood boards, cut into 75 mm strips. Each slab was 1200 mm long end-to-end and had a common rectangular cross-section 150 mm wide and 70 mm thick. The underlying poly-line V-shape of this structure produced nine formworks whose forms lay between a V and a rectangle, required measuring several non-orthogonal cuts with varying angles. This was a minor technical challenge, but was time consuming and would have benefited from digital fabrication resources. Grow-space was limited too; no more than 3 m × 3 m under a staircase. A moveable growing cart (Figure 9b) was improvised using three heavy-duty wire shelves, plastic zip ties, and black plastic sheeting. The cart had five 1220 mm × 1370 mm shelves, resulting in approximately 8.3 square meters of growing surface.

The final two workdays during the workshop were used to form and start growing the slabs. First, the inoculated hemp substrate had to be broken up until the fibers were completely loose (Figure 9c). As it was being fiberized, 250 g of kitchen flour was mixed for each 5 kg bag of living substrate. The flour was recommended by the manufacturer as a nitrogen-rich nutrient to promote the rapid growth of fungal hyphae, but for this project, the recommended quantity was doubled. The intention was to have the flour act as a temporary binder while the mycelia formed their bonds between fibers. Water was added to the extent that when a handful of fibers were squeezed, only one drop of water was released. Once fully prepared, the loose fibers were compacted by hand into the formworks on the plastic lined shelves of the cart (Figure 9d), and the wood formwork could be carefully slipped off, and reused to form multiples of the same shape (Figure 9e). As a means of providing a clean and humid environment to each slab, they were covered

in food-safe plastic film (Figure 9f). The cart was covered with a black plastic covering (Figure 9g) that kept the slabs in the dark while they grew, and, more importantly, provided a second means of keeping a clean and humid growing environment. Approximately one-third of the bags were used with two days of delivery to grow a first round of slabs. During the first week-long grow period, the students stored the remaining bags in a covered outdoor space, stacked on shelves and wrapped in black plastic sheeting. This was the best option due to the lack of access to large-scale cold storage. The bags encountered temperature swings between roughly −2 and 18 ◦C between day and night. of providing a clean and humid environment to each slab, they were covered in food-safe plastic film (Figure 9f). The cart was covered with a black plastic covering (Figure 9g) that kept the slabs in the dark while they grew, and, more importantly, provided a second means of keeping a clean and humid growing environment. Approximately one-third of the bags were used with two days of delivery to grow a first round of slabs. During the first week-long grow period, the students stored the remaining bags in a covered outdoor space, stacked on shelves and wrapped in black plastic sheeting. This was the best option due to the lack of access to large-scale cold storage. The bags encountered temperature swings between roughly −2 and 18 °C between day and night.

*Biomimetics* **2022**, *7*, 129 13 of 23

in approximately 8.3 square meters of growing surface.

*3.1. La Parete Fungina* 

Consequently, the formal character and complexity of each structure were intimately related to their respective method of myco-fabrication. Both were assumed to be compres-

For the structure grown by UVA students, pre-emptive planning took place two weeks before the workshop in January 2022. This included the development of the script described above in Section 2.1, hiring and coordinating with a research assistant at the UVA, and purchasing materials for the formwork. The five-day workshop was attended by undergraduate students from both engineering and design backgrounds during daily four-hour sessions. For the first three days of the workshop, the primary goals were fabricating the wooden formwork and creating a growing cart. Nine wooden formworks (Figure 9a) were hand-built from 17 mm unfinished whitewood boards, cut into 75 mm strips. Each slab was 1200 mm long end-to-end and had a common rectangular cross-section 150 mm wide and 70 mm thick. The underlying poly-line V-shape of this structure produced nine formworks whose forms lay between a V and a rectangle, required measuring several non-orthogonal cuts with varying angles. This was a minor technical challenge, but was time consuming and would have benefited from digital fabrication resources. Grow-space was limited too; no more than 3 m × 3 m under a staircase. A moveable growing cart (Figure 9b) was improvised using three heavy-duty wire shelves, plastic zip ties, and black plastic sheeting. The cart had five 1220 mm × 1370 mm shelves, resulting

The final two workdays during the workshop were used to form and start growing the slabs. First, the inoculated hemp substrate had to be broken up until the fibers were completely loose (Figure 9c). As it was being fiberized, 250 g of kitchen flour was mixed for each 5 kg bag of living substrate. The flour was recommended by the manufacturer as a nitrogen-rich nutrient to promote the rapid growth of fungal hyphae, but for this project, the recommended quantity was doubled. The intention was to have the flour act as a temporary binder while the mycelia formed their bonds between fibers. Water was added to the extent that when a handful of fibers were squeezed, only one drop of water was released. Once fully prepared, the loose fibers were compacted by hand into the formworks on the plastic lined shelves of the cart (Figure 9d), and the wood formwork could be carefully slipped off, and reused to form multiples of the same shape (Figure 9e). As a means

sion-bearing structures, even if they were not exhibited resisting external loads.

**Figure 9.** Preparation and process for forming and growing myco-material slabs: (**a**) re-usable wood formworks created in the first days of the workshop; (**b**) growing cart in its space under a staircase in the school of architecture; (**c**) fiberizing the living hemp substrate and mixing in additives prior to packing the formwork; (**d**) hand packing the wood formwork directly on the grow cart; (**e**) removing the mold for reuse; (**f**) slabs individually wrapped in food-safe plastic to keep the fibers humid and warm; (**g**) plastic "cloak" which covered the entire grow cart to keep growing specimens dark warm and humid; (**h**) myco-welding slabs with loose inoculated substrate as mortar. Photos by the author and Leila Ehtesham. **Figure 9.** Preparation and process for forming and growing myco-material slabs: (**a**) re-usable wood formworks created in the first days of the workshop; (**b**) growing cart in its space under a staircase in the school of architecture; (**c**) fiberizing the living hemp substrate and mixing in additives prior to packing the formwork; (**d**) hand packing the wood formwork directly on the grow cart; (**e**) removing the mold for reuse; (**f**) slabs individually wrapped in food-safe plastic to keep the fibers humid and warm; (**g**) plastic "cloak" which covered the entire grow cart to keep growing specimens dark warm and humid; (**h**) myco-welding slabs with loose inoculated substrate as mortar. Photos by the author and Leila Ehtesham.

In the weeks that followed the workshop, the UVA research assistant and one of the

participants continued to form and grow the remaining slabs while also myco-welding the slabs that were sufficiently cultivated. The living slabs were stacked into "chunks" between five and six layers thick, with loose substrate in between to level the assembly (Figure 9h). The assembly of living parts had to be completed in rigorously clean conditions, while keeping the assembly in the correct and intended configuration. While the slabs were being stacked, they were gelatinous and fragile and had to be handled with care by at least two people at a time. Furthermore, while slabs bonded and grew together, they needed to be kept in an appropriately clean, dark, warm, and humid environment. The wall chunks were grown into monolithic-like masses for roughly two weeks, after which they were passively dried until installation. At the time of assembly, all the myco-welded chucks had at minimum one week of In the weeks that followed the workshop, the UVA research assistant and one of the participants continued to form and grow the remaining slabs while also myco-welding the slabs that were sufficiently cultivated. The living slabs were stacked into "chunks" between five and six layers thick, with loose substrate in between to level the assembly (Figure 9h). The assembly of living parts had to be completed in rigorously clean conditions, while keeping the assembly in the correct and intended configuration. While the slabs were being stacked, they were gelatinous and fragile and had to be handled with care by at least two people at a time. Furthermore, while slabs bonded and grew together, they needed to be kept in an appropriately clean, dark, warm, and humid environment. The wall chunks were grown into monolithic-like masses for roughly two weeks, after which they were passively dried until installation.

drying time. The on-site installation of La Parete Fungina was completed in approximately one hour. The six wall chunks were driven to the site in a small passenger van. Wooden anchoring stakes (40 mm diameter) were driven into the ground and the base chunk was friction-fitted in place (Figure 10a). The remaining chunks were dry stacked (Figure 10b) each with similar wooden stakes in between. The simple friction-fitting system was ideally suited for this application, because the exhibition was temporary and needed to be taken down after a period of three months with minimal impact or damage to the UVA grounds. The two undulating units (Figure 10c) were approximately 1200 mm At the time of assembly, all the myco-welded chucks had at minimum one week of drying time. The on-site installation of La Parete Fungina was completed in approximately one hour. The six wall chunks were driven to the site in a small passenger van. Wooden anchoring stakes (40 mm diameter) were driven into the ground and the base chunk was friction-fitted in place (Figure 10a). The remaining chunks were dry stacked (Figure 10b) each with similar wooden stakes in between. The simple friction-fitting system was ideally suited for this application, because the exhibition was temporary and needed to be taken down after a period of three months with minimal impact or damage to the UVA grounds.

tall, configured in a manner such that the serpentine wall geometry produced a gap in the wall. The myco-welded objects were highly didactic due to their long growing time shown

following the installation, the structure was subjected to wind and snow, which did not cause a collapse, nor was the material compromised. The thick layer of overgrowth demonstrated its inherent resilience that would be well suited to its exhibition outdoors

for roughly two months, after which it was taken down.

The two undulating units (Figure 10c) were approximately 1200 mm tall, configured in a manner such that the serpentine wall geometry produced a gap in the wall. The mycowelded objects were highly didactic due to their long growing time shown through artifacts such as changes in color to the formation of fruiting bodies. In the days following the installation, the structure was subjected to wind and snow, which did not cause a collapse, nor was the material compromised. The thick layer of overgrowth demonstrated its inherent resilience that would be well suited to its exhibition outdoors for roughly two months, after which it was taken down. *Biomimetics* **2022**, *7*, 129 15 of 23

(**a**) (**b**) (**c**)

**Figure 10.** Installation of the prototype onsite: (**a**) friction fitting base chunk to the anchoring stakes in the ground; (**b**) friction fitting upper chunk of the myco-welded wall; (**c**) complete structure as it was exhibited at the biomaterials building exposition. Photos by the author and Leila Ehtesham. **Figure 10.** Installation of the prototype onsite: (**a**) friction fitting base chunk to the anchoring stakes in the ground; (**b**) friction fitting upper chunk of the myco-welded wall; (**c**) complete structure as it was exhibited at the biomaterials building exposition. Photos by the author and Leila Ehtesham.

### *3.2. L'Orso Fungino 3.2. L'Orso Fungino*

For the structure grown at K-State, pre-emptive planning took place for two weeks following the week-long workshop at the UVA. With the change in strategy for growing the wall chunks, notable adjustments to the scale and geometry were determined. An important driver was that the structure needed to be shipped 1800 km from Manhattan, Kansas, to Charlottesville, Virginia. Within the budget, two pallets could be sent (1220 mm × 1016 mm in area for each). Sized according to the freight limitations, wall units were designed, each approximately 750 mm long and 750 mm tall. The prototypes intended to demonstrate the wall units was vertically stacked in twos. The formwork was designed to be quickly assembled, collapsible, and re-usable. The rigid portion of the apparatus (Figure 11a) was created with a combination of hand-cut nominal timber frames, CNC-cut plywood panels, and 3 mm plastic laminations for surfaces in direct contact with living materials. The hand-stretched fabric portions (Figure 11b,c) were composed of breathable synthetic geotextile. Several formworks were fabricated so that multiple units could be grown simultaneously. For the structure grown at K-State, pre-emptive planning took place for two weeks following the week-long workshop at the UVA. With the change in strategy for growing the wall chunks, notable adjustments to the scale and geometry were determined. An important driver was that the structure needed to be shipped 1800 km from Manhattan, Kansas, to Charlottesville, Virginia. Within the budget, two pallets could be sent(1220 mm <sup>×</sup> 1016 mm in area for each). Sized according to the freight limitations, wall units were designed, each approximately 750 mm long and 750 mm tall. The prototypesintended to demonstrate the wall units was vertically stacked in twos. The formworkwas designed to be quickly assembled, collapsible, and re-usable. The rigid portion of the apparatus (Figure 11a) was created with a combination of hand-cut nominal timber frames, CNC-cut plywood panels, and 3 mm plastic laminations for surfaces in direct contact with living materials. The hand-stretched fabric portions (Figure 11b,c) were composed of breathable synthetic geotextile. Several formworks were fabricated so that multiple units could be grown simultaneously.

The first fabric formwork apparatuses were packed roughly one month before the opening of the exposition. Within the time constraints, two units could be packed by six people. As a safeguard from potential failures, additional units were accounted for in the materials budget. Due to a limited supply of materials, it was decided that nonsterilized and non-inoculated hemp fibers would be mixed in with the inoculated substrate to increase the yield volume. Several previous experiments in the MycoMatters Laboratory successfully propagated Ecovative materials into ratios of up to one part inoculated to four parts non-inoculated and non-sterilized hemp fibers (1:4) by volume. The fabric formworks were packed with a 1:2 ratio to increase the volume with less risk. In addition to the hemp, 250 g of kitchen flour per 5 kg bag of living material and water was added such as above.

**Figure 11.** Fabric formwork apparatuses: (**a**) rigid elements of the apparatus composed of wood and plastic laminate sheet where there would be contact with living materials; (**b**) upholstered formwork with black synthetic geotextile fabric; (**c**) top of the formwork apparatus showing the geotextile up-

holstered into the rigid frame. Photos by the author.

(**a**) (**b**) (**c**)

**Figure 11.** Fabric formwork apparatuses: (**a**) rigid elements of the apparatus composed of wood and plastic laminate sheet where there would be contact with living materials; (**b**) upholstered formwork with black synthetic geotextile fabric; (**c**) top of the formwork apparatus showing the geotextile upholstered into the rigid frame. Photos by the author. **Figure 11.** Fabric formwork apparatuses: (**a**) rigid elements of the apparatus composed of wood and plastic laminate sheet where there would be contact with living materials; (**b**) upholstered formwork with black synthetic geotextile fabric; (**c**) top of the formwork apparatus showing the geotextile upholstered into the rigid frame. Photos by the author.

For the structure grown at K-State, pre-emptive planning took place for two weeks following the week-long workshop at the UVA. With the change in strategy for growing the wall chunks, notable adjustments to the scale and geometry were determined. An important driver was that the structure needed to be shipped 1800 km from Manhattan, Kansas, to Charlottesville, Virginia. Within the budget, two pallets could be sent (1220 mm × 1016 mm in area for each). Sized according to the freight limitations, wall units were designed, each approximately 750 mm long and 750 mm tall. The prototypes intended to demonstrate the wall units was vertically stacked in twos. The formwork was designed to be quickly assembled, collapsible, and re-usable. The rigid portion of the apparatus (Figure 11a) was created with a combination of hand-cut nominal timber frames, CNC-cut plywood panels, and 3 mm plastic laminations for surfaces in direct contact with living materials. The hand-stretched fabric portions (Figure 11b,c) were composed of breathable synthetic geotextile. Several formworks were fabricated so that multiple units could be

**Figure 10.** Installation of the prototype onsite: (**a**) friction fitting base chunk to the anchoring stakes in the ground; (**b**) friction fitting upper chunk of the myco-welded wall; (**c**) complete structure as it was exhibited at the biomaterials building exposition. Photos by the author and Leila Ehtesham.

(**a**) (**b**) (**c**)

*3.2. L'Orso Fungino* 

grown simultaneously.

Within a four-hour work period, two formworks were filled with inoculated substrate (Figure 12a). The formworks were packed monolithically by hand and with the help of tools to compress the material around the perforated cardboard tubes (Figure 12b). Each unit used between nine and ten bags of pre-inoculated material due to overpacking, which caused the fabric to stretch, ultimately requiring more material to fill the formwork (Figure 12c). The formwork was then covered with a black plastic covering that kept the material humid and dark while the mycelium grew (Figure 13a). After the first two units were packed, a third was packed a day later. During the growth period of the first three units, approximately fifteen bags could be stored in the lab refrigerator. The remaining twenty bags (approximately) had to be kept on a pallet in the lab. After only four days, mycelium from the first two units had already grown through the stretched fabric (Figure 13b). The formwork of the first two units was removed (Figure 13c), which meant they would have two full weeks to passively dry in the lab before being shipped. The third unit became contaminated (Figure 13d) deep in the monolithic colony, despite that surface mycelium managing to grow in many areas. This suggested that a contaminant from the non-sterilized hemp and a lack of air were probably contributing causes. The first two formwork apparatuses were re-assembled and re-used to grow two more units. Of those two, one more unit became contaminated. The remaining three fabric-formed monolithic units and a wooden formwork apparatus were palletized (Figure 14a) and shipped to the UVA.

The on-site installation of L'Orso Fungino was completed in approximately two hours. The assembly of the prototype began by stringing cables through cardboard conduits of the lower wall unit (Figure 14b). The steel cables were mechanically fastened to the plywood base compression plate. Next, the cables were strung through the top wall unit (Figure 14c), this time with more difficultly because one of the cardboard tubes bent during the packing process. None of the units was fully dry which was an advantage because the cable could be forcefully pushed through the spongy mycelial matrix. Cables were mechanically fastened to threaded eyebolts. The stack of two units (Figure 14d) had a top plate that was put in compression by the tightening of each eyebolt against a washer (Figure 15a). The assembly was allowed to compress by one centimeter from post-tensioning. L'Orso Fungino was exhibited in the gallery at the School of Architecture at the UVA, alongside the third wall unit and the formwork apparatus (Figure 15b,c). The post-tension system was successful as a technique for stabilizing myco-structures. The connection details are in need of future iterations. A larger open question was how such post-tensioned wall structures would

*Biomimetics* **2022**, *7*, 129 16 of 23

as above.

**Figure 12.** Packing the fabric formwork apparatus with living myco-materials: (**a**) loose inoculated substrate was poured into the apparatus; (**b**) material was compressed into the form while minding the cardboard conduits; (**c**) apparatus almost full of inoculated substrate. Photos by the author. **Figure 12.** Packing the fabric formwork apparatus with living myco-materials: (**a**) loose inoculated substrate was poured into the apparatus; (**b**) material was compressed into the form while minding the cardboard conduits; (**c**) apparatus almost full of inoculated substrate. Photos by the author. *Biomimetics* **2022**, *7*, 129 17 of 23 *Biomimetics* **2022**, *7*, 129 17 of 23

(**a**) (**b**) (**c**) (**d**)

**Figure 13.** Growing fabric-formed monolithic wall units: (**a**) black plastic covered the formworks as the material grew in the MycoMatters Laboratory; (**b**) after four days of growth, healthy mycelium was found growing through the fabric; (**c**) first two fabric-formed monolithic units with all formworks removed after growing four days; (**d**) third unit found with a contamination compromising mycelial growth deep into the unit. Photos by the author. **Figure 13.** Growing fabric-formed monolithic wall units: (**a**) black plastic covered the formworks as the material grew in the MycoMatters Laboratory; (**b**) after four days of growth, healthy mycelium was found growing through the fabric; (**c**) first two fabric-formed monolithic units with all formworks removed after growing four days; (**d**) third unit found with a contamination compromising mycelial growth deep into the unit. Photos by the author. **Figure 13.** Growing fabric-formed monolithic wall units: (**a**) black plastic covered the formworks as the material grew in the MycoMatters Laboratory; (**b**) after four days of growth, healthy mycelium was found growing through the fabric; (**c**) first two fabric-formed monolithic units with all formworks removed after growing four days; (**d**) third unit found with a contamination compromising mycelial growth deep into the unit. Photos by the author.

**Figure 14.** Assembling the prototype: (**a**) palletized units and formwork apparatus before shipping to the UVA; (**b**) stringing cables from base plate through lower wall unit; (**c**) stacking two wall units while pulling tension cables through the assembly; (**d**) stacked undulating wall units before posttensioning. Photos by the author and Leila Ehtesham. **Figure 14.** Assembling the prototype: (**a**) palletized units and formwork apparatus before shipping to the UVA; (**b**) stringing cables from base plate through lower wall unit; (**c**) stacking two wall units while pulling tension cables through the assembly; (**d**) stacked undulating wall units before posttensioning. Photos by the author and Leila Ehtesham. the post-tensioning system was simple to disassemble at the end of the exposition. **Figure 14.** Assembling the prototype: (**a**) palletized units and formwork apparatus before shipping to the UVA; (**b**) stringing cables from base plate through lower wall unit; (**c**) stacking two wall units while pulling tension cables through the assembly; (**d**) stacked undulating wall units before post-tensioning. Photos by the author and Leila Ehtesham.

the plywood base compression plate. Next, the cables were strung through the top wall unit (Figure 14c), this time with more difficultly because one of the cardboard tubes bent during the packing process. None of the units was fully dry which was an advantage because the cable could be forcefully pushed through the spongy mycelial matrix. Cables were mechanically fastened to threaded eyebolts. The stack of two units (Figure 14d) had a top plate that was put in compression by the tightening of each eyebolt against a washer (Figure 15a). The assembly was allowed to compress by one centimeter from post-tensioning. L'Orso Fungino was exhibited in the gallery at the School of Architecture at the UVA, alongside the third wall unit and the formwork apparatus (Figure 15b,c). The post-tension system was successful as a technique for stabilizing myco-structures. The connection details are in need of future iterations. A larger open question was how such post-tensioned wall structures would support the load of a vault, a truss, or a beam. In its current state, the post-tensioning system was simple to disassemble at the end of the exposition.

unit (Figure 14c), this time with more difficultly because one of the cardboard tubes bent during the packing process. None of the units was fully dry which was an advantage because the cable could be forcefully pushed through the spongy mycelial matrix. Cables were mechanically fastened to threaded eyebolts. The stack of two units (Figure 14d) had a top plate that was put in compression by the tightening of each eyebolt against a washer (Figure 15a). The assembly was allowed to compress by one centimeter from post-tensioning. L'Orso Fungino was exhibited in the gallery at the School of Architecture at the UVA, alongside the third wall unit and the formwork apparatus (Figure 15b,c). The post-tension system was successful as a technique for stabilizing myco-structures. The connection details are in need of future iterations. A larger open question was how such post-tensioned wall structures would support the load of a vault, a truss, or a beam. In its current state,

The on-site installation of L'Orso Fungino was completed in approximately two hours. The assembly of the prototype began by stringing cables through cardboard con-

The on-site installation of L'Orso Fungino was completed in approximately two hours. The assembly of the prototype began by stringing cables through cardboard con-

support the load of a vault, a truss, or a beam. In its current state, the post-tensioning system was simple to disassemble at the end of the exposition. work apparatuses were re-assembled and re-used to grow two more units. Of those two, one more unit became contaminated. The remaining three fabric-formed monolithic units and a wooden formwork apparatus were palletized (Figure 14a) and shipped to the UVA.

The first fabric formwork apparatuses were packed roughly one month before the opening of the exposition. Within the time constraints, two units could be packed by six people. As a safeguard from potential failures, additional units were accounted for in the materials budget. Due to a limited supply of materials, it was decided that non-sterilized and non-inoculated hemp fibers would be mixed in with the inoculated substrate to increase the yield volume. Several previous experiments in the MycoMatters Laboratory successfully propagated Ecovative materials into ratios of up to one part inoculated to four parts non-inoculated and non-sterilized hemp fibers (1:4) by volume. The fabric formworks were packed with a 1:2 ratio to increase the volume with less risk. In addition to the hemp, 250 g of kitchen flour per 5 kg bag of living material and water was added such

Within a four-hour work period, two formworks were filled with inoculated substrate (Figure 12a). The formworks were packed monolithically by hand and with the help of tools to compress the material around the perforated cardboard tubes (Figure 12b). Each unit used between nine and ten bags of pre-inoculated material due to overpacking, which caused the fabric to stretch, ultimately requiring more material to fill the formwork (Figure 12c). The formwork was then covered with a black plastic covering that kept the material humid and dark while the mycelium grew (Figure 13a). After the first two units were packed, a third was packed a day later. During the growth period of the first three units, approximately fifteen bags could be stored in the lab refrigerator. The remaining twenty bags (approximately) had to be kept on a pallet in the lab. After only four days, mycelium from the first two units had already grown through the stretched fabric (Figure 13b). The formwork of the first two units was removed (Figure 13c), which meant they would have two full weeks to passively dry in the lab before being shipped. The third unit became contaminated (Figure 13d) deep in the monolithic colony, despite that surface mycelium managing to grow in many areas. This suggested that a contaminant from the nonsterilized hemp and a lack of air were probably contributing causes. The first two form-

(**a**) (**b**) (**c**)

**Figure 15.** Post-tensioning and exhibiting the prototype: (**a**) tightening the internal cables to add compressive force to the assembly; (**b**) gallery installation with stacked units and wood formwork; (**c**) wall prototype during exhibition opening at the UVA. Photos by the author and Leila Ehtesham. **Figure 15.** Post-tensioning and exhibiting the prototype: (**a**) tightening the internal cables to add compressive force to the assembly; (**b**) gallery installation with stacked units and wood formwork; (**c**) wall prototype during exhibition opening at the UVA. Photos by the author and Leila Ehtesham.

### *3.3. Discussion and Future Work 3.3. Discussion and Future Work*

La Parete Fungina and L'Orso Fungino both served as demonstrations of wall assembly systems that challenged the status quo of myco-fabrication. Myco-welding and fabricforming techniques were tested for their capacity to create complex yet efficiently formed wall structures from large building units grown in re-usable formwork systems. The structures initiated a new dialog of architecture-scale myco-fabrication techniques that were positioned between those which used building units the size of a brick and those which used units the size of a room. They demonstrated the flexibility and ease with which myco-materials could adapt based on available tools, materials, and knowledge. La Parete Fungina and L'Orso Fungino both served as demonstrations of wall assembly systems that challenged the status quo of myco-fabrication. Myco-welding and fabricforming techniques were tested for their capacity to create complex yet efficiently formed wall structures from large building units grown in re-usable formwork systems. The structures initiated a new dialog of architecture-scale myco-fabrication techniques that were positioned between those which used building units the size of a brick and those which used units the size of a room. They demonstrated the flexibility and ease with which myco-materials could adapt based on available tools, materials, and knowledge.

Working in educational contexts, the strategies generated material knowledge directly through the production of physical artifacts. For novice student collaborators, this approach was productive toward fostering their appreciation and mastery of building material assemblies through the technical lens of myco-materials. Furthermore, students had the freedom to exercise their creativity and experience working at full-scale through experiments that left room for improvised adjustments. Insights on the craft of growing myco-structures were never assumed, were developed directly in collaboration with the students, and generated through creating. The students learned first-hand that building (with any material) is challenging, but also joyful and rewarding. Thus, the impacts of the methods presented below were both technological and educational. Myco-materials were challenging for students because they required greater care and attention compared to common, inert materials. For example, compared to handling live materials, personal protection practices, including wearing masks and gloves and thoroughly cleaning all working surfaces and formwork, are not an inherent protocol for a typical design or engineering student. Lessons learned through minor frictions, failures, and contaminations were vital to provoke important questions about the material ethics and the appropriateness of Working in educational contexts, the strategies generated material knowledge directly through the production of physical artifacts. For novice student collaborators, this approach was productive toward fostering their appreciation and mastery of building material assemblies through the technical lens of myco-materials. Furthermore, students had the freedom to exercise their creativity and experience working at full-scale through experiments that left room for improvised adjustments. Insights on the craft of growing myco-structures were never assumed, were developed directly in collaboration with the students, and generated through creating. The students learned first-hand that building (with any material) is challenging, but also joyful and rewarding. Thus, the impacts of the methods presented below were both technological and educational. Myco-materials were challenging for students because they required greater care and attention compared to common, inert materials. For example, compared to handling live materials, personal protection practices, including wearing masks and gloves and thoroughly cleaning all working surfaces and formwork, are not an inherent protocol for a typical design or engineering student. Lessons learned through minor frictions, failures, and contaminations were vital to provoke important questions about the material ethics and the appropriateness of the methods.

the methods. Rather than demonstrate methods ready to grow buildings entirely from myco-materials the prototypes suggested new hybrid techniques that could contribute to the broader cannon of myco-fabrication; adding to well-established discrete element, 3D printing, and monolithic techniques. The prototypes detailed above operated between the scales of a brick and a monolithic pavilion. At the scale of a house (for example), a building structure grown from myco-materials would likely require multiple prefabricated units or "chunks" that would be assembled on-site. Without commercial-scale growing resources, there are practical and biological limits to the scales of colonies one can grow. The Monolito Micelio [47] was 2.5 m × 2.5 m × 2.5 m, and its scale presented several notable Rather than demonstrate methods ready to grow buildings entirely from mycomaterials the prototypes suggested new hybrid techniques that could contribute to the broader cannon of myco-fabrication; adding to well-established discrete element, 3D printing, and monolithic techniques. The prototypes detailed above operated between the scales of a brick and a monolithic pavilion. At the scale of a house (for example), a building structure grown from myco-materials would likely require multiple prefabricated units or "chunks" that would be assembled on-site. Without commercial-scale growing resources, there are practical and biological limits to the scales of colonies one can grow. The Monolito Micelio [47] was 2.5 m × 2.5 m × 2.5 m, and its scale presented several notable disadvantages, including the significant demand for time and labor, the risk of handling such significant quantities of living material in uncontrolled environments, the need for pliable

internal reinforcing, and the challenge of drying large colonies to stop growth without large ovens. While there were few active energy inputs needed to grow the myco-materials, the near-ubiquitous plastic formworks in which they were grown presented an ethical dilemma. The plastic-lined plywood and woven nylon fabric formwork system that formed the Monolito Micelio were a waste byproduct that resulted in landfill disposal. However, if a sufficient volume of living myco-materials was available and there was enough funding to hire labor for such a project, most of the formwork could have been reused to create several pavilion-scale units that could be aggregated to form larger spaces. This suggested that the techniques demonstrated by the Monolito Micelio could be scaled to grow parts two to four times larger. The goal for myco-fabrication in architecture should be to develop the capacity to grow parts at the same scale as current glue-laminated and cross-laminated timber manufacturing.

Experimentation with myco-fabrication at architectural scale is still nascent as a field and faces massive challenges that need to be overcome to achieve results other than prototype structures and fanciful pavilions. Limitations for building-scale deployments of myco-materials are foremost caused by the challenge of supply and access to commercial quantities of material. Currently, the lack of myco-material production infrastructure makes it both energetically and financially costly to transport wet, living mycelium composites over long distances. Ecovative, which is based in Troy, NY, has pioneered the scalingup of myco-material production by closely studying and collaborating with commercial mushroom farming industries, especially in the neighboring state of Pennsylvania, where over 60% of all mushrooms in the United States are grown [58]. As a result, they offer a biotechnology that grows quickly and reliably under favorable environmental conditions and with some resilience to contamination. The ability to grow mycelium entirely through the lignocellulosic substrate within just a few days is a major advantage that makes growing structures a relatively fast process. However, such speed and reliability come with costs that can be a barrier to using myco-materials at a large scale. Beyond the cost of the material itself, the need to hire expedited refrigerated transport and have access to large-scale refrigerated storage are other potential barriers.

Radical approaches to sustainable construction raise questions of material ethics when evaluating what and how much was wasted in different approaches to myco-fabrication. Although in many regional contexts myco-material technologies have the capacity to require less energy than petrochemical foams and plastics they seek to replace, there are critical ethical questions that must be considered. In addition to the near-ubiquitous use of plastic and issues of waste-producing formworks, transporting myco-materials long distances with petroleum-consuming vehicles should be scrutinized. For the prototypes presented here, live myco-materials were procured from Ecovative's spawn supplier in Pennsylvania and transported either to the UVA or K-State. For both, it was cost-prohibitive to hire a refrigerated truck to deliver from the spawn supplier directly to the university. Thus, more improvisatory and self-motivated methods were needed. For the UVA-grown structure, shipping delays were going to have the material arrive after the workshop was over. To keep the project on schedule, the author drove a 750 km round-trip to the spawn supplier. For the structure grown at K-State, creative logistical planning was required to organize a two-step relay delivery. For a pro-rated cost, the pallet was first "hitch-hiked" 1700 km with a scheduled refrigerated shipment of button mushrooms spawned on a farm in the neighboring state of Oklahoma. Research assistants in the MycoMatters Laboratory then drove an 800 km roundtrip to bring the pallet back from the farm. It would be ideal for the distribution of myco-materials to exist in a model where they are regionally produced as a way of reducing transportation distances. More immediately, the opportunity to overlay the myco-material demand with existing food supply chain maps from existing spawn suppliers presents an opportunity to cultivate deep bonds between agriculture and biomaterial industries.

For myco-materials to succeed in the future, they must remain in the current dialog, both in academic and professional contexts. Collaborations across the fields of design,

engineering, biological sciences, agriculture, and economics (for example) are essential to developing new knowledge essential for the scaling of new material technologies in ways relevant to building construction. Importantly, knowledge about growing structures must be as commonly accessible such as knowledge needed for building with wood, steel, or concrete. The craft of growing myco-structures is clearly in need of time to mature, but will only do so through continued study and experimentation. Future work should seek cooperative logics between fungal growth, computational design, and digital fabrication to further discover constructive possibilities with myco-materials. For example, digital reference technologies, such as 3D-scanning and augmented reality, may be important components of future work on myco-welding. The ability to grow twine and other natural-fiber textiles into the material matrix suggests that through computational design and analysis, the strategic placement of such reinforcements could be deployed to selectively strengthen and enhance myco-materials. Such advancements could help fully integrate forming materials into the building components being grown. Pre-stressing and post-tensioning have probable futures in myco-fabrication for certain structural scenarios. Robotic fiber winding and CNC knitting are two technologies that have been widely demonstrated and could be immediately applied in the context of myco-fabrication. The raising popularity of "co-bots" also suggests a future in which machines could collaborate with craftsmen and carry out improvisational tactics with greater precision, reduced demand for labor, and potentially much safer and cleaner fabrication conditions.

### **4. Summary and Conclusions**

There is an urgent need for low-energy and renewable building materials that divert building and demolition waste from landfills and lessen the impact of the construction industry on climate change. The ability to rapidly grow building structures from mycomaterials, particularly for short-term or temporary functions, has the potential to greatly reduce building and demolition waste. This paper provided an extensive overview of the state-of-the-art in deploying myco-materials at the architectural scale, highlighted the numerous case studies of researchers in diverse global contexts growing building-scale structural parts and pavilions, and gave first-hand insight about the significant challenges and limitations associated with the application of myco-materials for architectural structures. The applied research presented here developed hybrid myco-fabrication techniques that overcame the challenge of cultivating large colonies of living myco-materials into precise forms, and demonstrated intuitive and re-usable formwork systems that reduced waste byproducts from growing and fabrication processes. The techniques were developed in academic environments that gave young designers and engineers the access, space, and resources for working with myco-materials. The two prototype wall structures demonstrated the ability to grow large and complex shapes outside of rigorously controlled biolab environments, and with fewer risks than monolithic structures grown in situ. The lightweight properties of mycelium composites were an advantage in this context, where large, complex building components could be pre-grown and pre-dried off-site in semicontrolled environments and assembled with less continuous on-site labor compared to the production of brick/block or monolithic mycelium structures.

Realistically, the greatest potential for these techniques is in applications that replace EPS and other varieties of foam and insulation materials for insulated concrete formworks, large-scale acoustical arrays, temporary self-supporting structures, interior furnishings, scenography or theatre stage projects, and others, leveraging the inherent absorptive, insulative, and fire-resistant properties of myco-materials. Whether these techniques are applicable to load-bearing building structures is still an open question that demands further research. Nonetheless, large-scale building and long-span myco-material structures continue to gain interest in trends of research and commercialization that seek to vastly offset the impact of the short lifespans of buildings in the modern era.

**Funding:** The 2022 biomaterial building exposition was hosted by the University of Virginia School of Architecture and funded by The Jefferson Trust and the Center for Global Inquiry & Innovation. Additional funding for student research assistants was provided through the Kansas State University Global Food Systems Seed Grant Program during the 2021–2022 funding period.

**Acknowledgments:** The work presented here would not have been possible without the research assistants Leila Ehtesham, Annabelle Woodcock, Holly Ellis, and Emmett Lockridge. Thanks to the students in the UVA workshop: Josh Cauthen, Abby Hassell, Mak Johansen, Jacob McLaughlin, and Ryan Naddoni. Additionally, thanks to the students in the MycoMatters seminar: Matthew Fuller, Eduardo Granillo, and Joey Jacobs. Additional thanks to Joe Hornung, Richard Thompson, Lisa Schubert, Katie Kingery-Page, and Dean Tim de Noble from the College of APDesign at Kansas State University for their belief in and support of this research.

**Conflicts of Interest:** The author declares no conflict of interest.
