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A CAD drawing of straw panels

Straw-SIPs appear on the cusp of a breakthrough. Has their time finally arrived?

An Opening
The U.S. building industry is beset with crisis: how to reduce both the operational and embodied carbon of buildings while constructing homes faster than ever to mitigate a severe housing shortage with a critically diminished and underskilled workforce, volatile material supply chains, a dearth of domestic manufacturing innovation, and a culture mired in conservatism and inefficiency? The juggernaut of conventional construction is faltering and appears vulnerable to influence.
There are intimations of an industry wide focus on embodied carbon. The lumbering U.S. Green Building Council (USGBC, administrators of the contentious LEED rating system) is starting to press for full lifecycle emissions accounting. Environmental, Social, Governance (ESG) reports are coercing high volume corporate builders to hit emissions budgets or risk disinvestment. Yet history indicates that entrenched industrial actors and the fortress of capital behind them will continue to stumble over their own buttresses as they attempt to navigate the economic transition away from fossil fuel and extraction based technologies. Biden himself has earmarked $2 billion to build “low-carbon” federal facilities, but he’s spending it on “low-carbon” asphalt, concrete, glass, and steel. Institutional finance is hopelessly addicted to dubious direct carbon capture systems and offset credits.
Meanwhile, research has conclusively shown that a mass adoption of bio-based materials with carbon sequestering properties—straw in particular—is the best and perhaps only strategy to decarbonize the construction sector with any meaningful rapidity. In September of 2023, the U.N. Environment Programme published a comprehensive report on embodied carbon in building materials that features a prominent section discussing biomass. Nonprofits like Rocky Mountain Institute (RMI) and the International Energy Agency (IEA) have published corresponding findings and recommendations. Architects of the high-performance/high-design disposition are publishing manifestos with titles like Manual of Biogenic House Sections (LTL Architects) and Material Reform (Material Cultures).
Natural building communities have striven for decades to establish straw as a viable building material, but have until recently focused primarily on fostering labor intensive hand-stacked straw bale construction methods. Progressive architects, engineers, and builders have incrementally refined the method of straw bale construction such that the best built straw bale homes rival the performance, durability, and comfort of high-end, high-tech construction—all while dramatically undercutting their embodied carbon. But this method is optimized for the communities from which it arose: scrappy owner/builders, rural homesteaders, off-grid aspirants, communities isolated from speculative development and state funds, DIY enthusiasts, and radical idealists. Its constraints are those that these communities are often willing to work within, but that standard construction practices cannot abide: ample amounts of time, space, and informal labor.
Outside of these communities, bale building is rarely viable unless a client can alleviate those constraints with money. Even then, an aspiring owner of a straw building uninterested in building it themselves is faced with the principal challenge of natural construction: the esotericism of the method. Generously estimating, there are a handful of licensed architects and builders scattered throughout the U.S. that are willing and able to build a high quality permitted straw bale building. These are the factors that have tapered the growth in bale building rates, regardless of the physical viability and code acceptance of the method. If straw building advocates hope to significantly influence carbon-drawdown or the accessibility of climate-resilient shelter, they will have to transition to methods that are more compatible with industry standards.
For decades, prefabricated straw building systems have quietly persisted as a promising curio, but a contemporary surge of producers has engendered hope of a breakthrough. Savvy upstarts are synthesizing high-performance design with carbon sequestering materials through the development of straw filled, wood-framed Structural Insulated Panels (SIPs) that are quickly installed and compatible with conventional workflows. Straw-SIPs attempt to take the challenges of bale building and invert them: if stacking straw bales seems slow and unruly to the uninitiated, what could appear more efficient and accessible to the U.S. construction industry than a wood framed box? Amidst a climate emergency and a rapidly transforming landscape of design and construction, the moment may finally be ripe to establish straw within a new “carbon architecture” via prefabricated panels, bringing the performance benefits and climate solutions offered by straw building—and perhaps some of the essential ethos of the natural building movement—up to the scale of the crises at hand.
An Accidental Innovation
In 2000, upon embarking on a tour to promote their new book, Straw Bale Building, Chris Magwood and Peter Mack, co-founders of Camel’s Back Construction of Ontario, decided to build a transportable wall section to provide a physical demonstration of their bale building system. Their system relied on a structural wood frame to carry the load of the roof, with straw bales filling the space between the studs, thus a section of their wall was a wooden box filled with bales. That same year, Camel’s Back was asked to build a full scale single room straw bale building display at the Toronto Home Show. Given the impracticality of performing the messy, arduous task of constructing and plastering a bale building inside an exposition venue within a short time window, the team decided to experiment with a rudimentary form of wall prefabrication. They built and base coat plastered wall segments in Magwood’s barn then delivered them to the show floor, where they were placed via small mobile cranes, fastened together, roofed, and finished with plaster. The fundamental benefits of prefabrication began to reveal themselves: the off-site work was less laborious and more organized; the installation process went quickly and smoothly. “I can still feel the high that came along with watching this crazy idea prove itself to be extremely feasible,” Magwood wrote 15 years later.
After the home show, Magwood traveled to an Australian straw bale conference to share his ostensible breakthrough, only to encounter two other prefabricated straw pilot projects presented at the conference, from the U.K. and Australia. Back in Canada, prefabricated straw made more headway. Ben Polley, a student of Magwood and a member of his team from the Toronto show, built a full scale home from straw panels for another home show in 2003. After the show, Polley disassembled and reassembled the building on a permanent site, and it has remained occupied ever since. In 2009, another student of Magwood, with his ongoing consultation, founded NatureBuilt, a company that exclusively manufactured and installed prefabricated straw wall panels. NatureBuilt refined the panel proof of concept and completed at least 16 projects in their six years of operation. They demonstrated that straw panels could be viable outside of single story residential buildings, successfully installing warehouse sized commercial structures and multi-story buildings.
In 2015 Magwood compiled his community’s experience into a book: Prefab Straw Bale Construction. He called the building system Straw Structural Insulated Panels (S-SIPs), conceptually associating the method with other SIP systems that had slowly gained traction within the conventional building world. The book was acclaimed by Magwood’s peers as “a blueprint for regenerative housing for the masses,” “a giant leap forward,” “not a minute too early,” and, evidently in hindsight, “way ahead of the curve.” “I don’t think of it as being necessarily all that influential. It didn’t sell very many copies…” Magwood told me when I asked about its impact. North American prefab straw languished for a few years.
The Europeans Race Ahead
Straw-SIP development has continued apace across the Atlantic. ModCell, one of the presenters at the straw building conference Magwood attended back in 2000, is still thriving in England, having completed a wide array of projects including several schools and commercial buildings. There are several established straw-SIP companies throughout France, where multi-story projects and radical retrofits in central Paris have demonstrated the viability of urban straw construction. Prefab straw is quickly gaining traction in Germany.
EcoCocon, headquartered in Slovakia with production based in Lithuania, is the most established straw-SIP manufacturer and is known around the world, largely due to their slick marketing and their willingness to ship their panels internationally. In the past 15 years they have delivered over 300 buildings and production is increasing rapidly. They have recently captured the attention of American architects and builders. In 2019 Peter Jensen founded the New York based construction firm Build With Nature to bring EcoCocon’s panels to the U.S. Jensen has since imported and installed seven projects in the Northeast, and 10 more buildings are in development at time of writing.
Jensen, a Danish born savant who spent decades studying vernacular natural building techniques around the world, ascribes Ecocon’s success to the exacting precision and quality of their engineering and manufacturing, and to their rigorous testing and third party certifications. EcoCocon’s panel differs from Magwood and other’s early designs by compressing loose straw into a wooden frame using a proprietary process. Instead of filling a wall with intact bales, the wall itself becomes, essentially, a bale with consistent density throughout the wall. This subtle modulation requires investment in specialized machinery or, as discussed later, a spark of ingenuity. The panels are Passive House certified to be highly insulated with minimal thermal bridging; Cradle to Cradle certified to be environmentally and socially responsible; fire-rated at 120 minutes (by an E.U. certification body); and are constructed from Forest Stewardship Council (FSC) certified sustainable lumber. Builders report them to be a pleasure to install (“like Lego blocks,” is the common refrain). But until EcoCocon establishes a production facility in the U.S. (which Jensen told me is a possibility), the carbon sequestration of their U.S. projects will remain significantly compromised by cross-Atlantic transportation emissions.
A hand drawing of a couch
Home Grown
At a 2017 conference of the California Straw Building Association (CASBA), Craig White, founder of ModCell, the UK based straw-SIP producer, presented an argument for prefabrication that spurred a small flurry of panel interest and development in the U.S. In 2022, CASBA hosted a discussion between straw panel producers presenting designs from around the country. One featured panel was developed by New Frameworks Design/Build of Essex, Vermont, a worker-owned cooperative at the forefront of high-performance natural construction and intimately involved in natural building communities.
New Frameworks had long established a successful general contracting business that specialized in both straw bale and conventional typologies augmented with natural materials and progressive building science. In 2018, a year before the first EcoCocon panels landed in the U.S., New Frameworks was solicited to build a high-performance straw building in Massachusetts. The project was a perfect fit for their ethos and skillset, but they were increasingly reluctant to travel for personal, economic, and ecological reasons. Inspired by the precedent of ModCell and EcoCocon, and with the guidance of Magwood’s experience and book, they developed a prototype straw-SIP to make the project viable. New Frameworks consulted on the building design, prefabricated the panels in Vermont, then shipped and installed the walls.
The project was a success, and panel fever soon struck New Frameworks. “I don’t know if I will ever build a site-built, straw bale building again,” co-founder and general director Ace McArleton told me. Now they build walls in a workshop, and New Framework’s business model has become almost solely focused on straw panels. Production is steadily increasing, and to date they have completed around 20 panel projects.

 

(Read the full interview with Ace McArleton here)

The other extant straw-SIP producer in the U.S. had no prior ties to the natural building movement before their fervent embrace of straw. Andrew Frederick, a Maine-born carpenter and building scientist, attended a Passive House conference in 2019 where a speaker presented Magwood’s calculations that showed the staggering difference in embodied carbon between typical high performance products and bio-based materials like straw. Frederick described his exposure to this data as a, “PowerPoint-induced out-of-body experience.” Looking around the room at his colleagues, he mused that none of them were financially positioned or professionally willing to alter their business structures, and began to feel a sense of obligation.
As a lone consultant and carpenter, Frederick told me, he “had the luxury at the time of being like: I’m just gonna put my foot down.” He was suddenly certain he wanted to build only with straw and figured he would have to prefabricate panels under a roof in the perpetually wet climate of the Northeast. I asked if he had ever worked with straw before attempting to design a straw-SIP. “No, never. Two days after I got home from that conference, I got four bales of straw and made a little panel on my porch.” Around the same time, a client asked him to build a house. Frederick insisted that the exterior envelope be composed of straw panels or he wouldn’t build it. They said yes. In December 2019, Frederick rented a bare warehouse and began building out a workshop. On March 23, 2020, he received his first delivery of straw bales. Within a week, he had built his first prototype based on EcoCocon’s model of loose straw compressed within a wood frame (utilizing an ingenious jig involving ratchet straps), but added additional details more suited to U.S. building practices. By August 6, 2020, the panels were installed on the client’s site, and his new company, Croft, was born.
Croft is now a rapidly growing straw-SIP producer that employs around a dozen carpenters in mid-coast Maine. They have already outgrown their first workshop, and moved into a 14,000 SF space in April 2023. They are publicly radical in their ambition to build faster and better (both qualitatively and ecologically) than conventional builders. They have provocatively called themselves a “carbon capture company whose by-product is houses.” At time of writing, Croft has completed nine projects since 2020, and four more are scheduled to be completed this winter.
(For an in depth look at a Croft project, see “A House for a Farmer” in Issue No. 74 of The Last Straw)
The Task at Hand
While Jensen, McArleton, and Frederick have developed and established viable business models for small-scale straw-SIP production, their ambitions and insights reach far wider. Our discussions inevitably turned toward the future of straw, construction, and labor, with questions of scale and mass adoption persisting throughout. “We are living in the twilight of resource extraction,” Frederick mused, “how do we get out of the world of being required by code to use an intense amount of resources and materials that often results in a building that only lasts for 75 years, but we’re using like 300 years worth of resources to [build it]?” McArleton wondered how to, “house people in the way that we need to house them, to face the crises [of climate and capital], to face the starvation of [ecological resources] that we’re now at the end of.” Jensen was adamant that straw builders deeply engage with the agricultural industry and push for carbon sequestering tilling methods. These are questions beyond the scope of small panel producers, yet the pioneers of straw-SIPs are keen to ask them. How will straw-SIPs face the challenges ahead?
A drawing of a horse standing on a wheeled platform
A Trojan Box
Straw-SIPs can offer faster build schedules than even standard stick-framed wall systems. Given the glaring crisis of housing shortages across the US, this could be the most attractive feature of straw-SIPs for hesitant developers, contractors, and legislators. But off-site and modular construction methods, even when built with standard materials, have been stubbornly resisted by the building industry for decades, and have only recently established a precarious foothold. Mark Erlich, a master carpenter, labor union leader, and historian, in his 2023 book, assesses the slow rise of off-site construction as part of an inevitable, “gradual long-term deskilling trend of specialization and the shift from fabricator to installer.” While builders today may balk at the suggestion that walls be ordered and delivered, it was not long ago that it seemed just as absurd to a finish carpenter to not just build a door from scratch onsite.
While Erlich recounts stories of the hubris and spectacular failure of modular construction firms aspiring to “disrupt” the industry through massive, high-risk investments, he notes that “the companies that appear to be stable and successful are those with construction experience and a sharper focus that is less susceptible to the call of the disruptive siren.” Of note is the example of Bensonwood Homes of New Hampshire, founded as a small timber framing contractor in the 1970s that now—after a $13 million dollar investment—produces around 300 prefabricated high-performance homes per year and employs over 100 people in its offices and workshops.
Magwood predicts that, “a lot of the labor shortages in the construction sector now are going to play in favor of more panelization.” As contractors face a dwindling pool of stick framers, placing an order for walls that show up on schedule becomes increasingly appealing. Magwood is optimistic about taking advantage of this trend toward prefabrication as an opportunity to package straw in a standardized box. “One of the push backs against new materials is that the trades don’t know how to install them or how to work with them. If you panelize it, now only the people making the panel have to know that, and the person installing the panel only has to know what fastener to put in and where.” The trojan horse approach of pushing straw into buildings was echoed by Frederick. During his successful agitations against foam insulation at his prior employer Frederick assessed that, generally, “people don’t actually care [what a building is made of], and you can use that to your advantage.”
Straw-SIPs can only compete economically with other building typologies if they reach a sustainable volume of production. Magwood warns that “specialty, custom, owner-driven kinds of projects,” will keep straw trapped within a niche market. He suggested that panel producers would be wise to work with developers (or become developers) and transition to more iterative projects to fully reap the efficiencies of prefabrication: “Even at that small scale [of 10-12 similar designs], that’s where it hits its sweet spot.” Frederick quietly told me he wants to phase out single-family builds altogether, and above all Croft aims to increase production speed. Both Croft and New Frameworks have begun selling pre-designed ‘kit’ homes to contractors and DIY owners in an effort to increase accessibility by reducing design costs. EcoCocon is waiting for a large enough project or developer to incentivize the construction of a U.S. plant.
A drawing of seeds
Sowing Seeds
While the current panel producers are all aiming to increase their production, they acknowledge that there is a crucial geographic limit. It is untenable, ecologically and economically, to ship straw (panelized or otherwise) long distances. Straw panel production must be localized around straw producers, and projects utilizing those panels must be built nearby to avoid transportation emission overhead. Magwood sees this geographic constraint as an economic boon to deindustrialized communities:
“It makes a lot of sense in a farming town—in which whatever manufacturing was there left 30 years ago—if you put together a small factory with a couple million dollars of investment and make enough stuff to supply whatever building is going on nearby. I think there’s a lot more appetite for that kind of regional development. They’ll invest in that because it’s better for the local economy than to be importing from outside.”
With legislative inclinations leaning back toward industrial development, and sustainable objectives vaguely sewn into those investment packages, there may be opportunities to fund such projects.
Luckily, it is not a particularly daunting task to get started with panel production. “There’s no heavy investment in heavy equipment… This light industry and light manufacturing is technology that we all have access to,” McArleton affirmed. New Frameworks has already begun the process of spreading panel production through the dispersed, collaborative sharing of resources, “I’m calling it our ‘seed strategy.’” Their first partner is Joe Silins, a straw bale builder in Tuscon, Arizona, who visited New Frameworks and was inspired to launch his own straw panel business with their consultation.
A drawing of two hands moving toward a clasp
Sustainable Labor
McArleton ascribes the staggering industry wide contraction of trades workers to a construction culture that propagates a lack of care for training, safety, craftsmanship, solidarity, and inclusivity. While New Frameworks, a “multi-racial, women-, queer- and trans-owned worker cooperative,” has already taken great strides toward remediation of that culture within their business, McArleton has found that prefabrication provides more tools to that end. The comfort, safety, and consistency of off site work has raised morale and proved more conducive to training when compared to the dynamic (read: chaotic) context of a jobsite that is often a hindrance to workforce development.
McArleton hinted of a greater sense of fulfillment that has spread through New Frameworks’ panel production shop. The gathering of workers into a centralized and stable location is indeed in itself a radical cultural shift from the small firm/independent contractor paradigm. The dispersed and isolated nature of independent onsite work is arguably a primary driver of the alienation and disillusionment that abounds on conventional job sites. The possibility that offsite straw-SIP production may be able to foster a sense of solidarity unique to trades work—establishing the communal and dignified ethos of straw bale building within a viable business structure—must not be discounted.
If straw-SIPs successfully proliferate at an industry wide scale, however, likely cooptation from large industry actors will make it imperative to fight for equitable and ethical structures of labor. The greater potential for solidarity in panel production work may be a boon to unionization efforts in the notoriously difficult to organize residential subsector. McArleton, who entered the trades as a union apprentice, is hopeful; Magwood told me he sees a much easier path to unionization for panel fabricators than for the rest of the onsite residential workforce; and Erlich’s book relates a story of a large scale modular construction firm in the San Francisco Bay Area that has successfully cooperated with a local carpenters union to provide and train their workforce.
Another crucial threat to labor that comes with prefabrication and standardization must be considered. Though the construction sector has historically boasted its invulnerability to the threat of full automation that has ravaged labor conditions in other industries, that status quo may not hold for long. EcoCocon is launching a fully automated straw panel production facility in Slovakia in 2024. If straw-SIP labor fails to organize from the onset, there could soon be no labor left to organize.
A drawing of a winding river
Bending the River
Is an inflection point finally upon us? There appears to finally be a mass market trend toward sustainable materials driven by grassroots development and advocacy, consumer consciousness, and legislative influence. While monopolized industry drags its feet, can human-scaled light industry take advantage of this opening?
Frederick has tentative optimism for harnessing market forces, “I think the key… is to pay attention to currency as a signal. If people are willing to line up and pay for the solution you are offering, then there’s a good chance that that solution can be grown and scaled and work in other markets too.” Given that Croft is scheduled to build straw-SIP homes for the next three years, it appears that many Mainers have affirmed his speculation. McArleton, who can reasonably be called a visionary of natural building, and has staked New Frameworks’ fate on panel development, sees the belated general acknowledgment of the twin crises of climate and capital as an opportunity for, “a new vision and a new practice.”
That new vision is spreading. In early November 2023, New Frameworks, Croft, and EcoCocon convened with dozens of progressive industry actors—suppliers, manufacturers, designers, consultants, developers, builders, academics, and policy makers—to hold the first meeting of the Northeast Biomaterials Network, which asks, “How can regionally produced, renewable building materials be brought to market, at scale, across the Northeast?” The fate of straw building—if not the construction sector at large—rests upon the answers produced by organizational efforts like these. If executed with great care, the development and spread of straw-SIP systems could be the pivotal tool with which the straw building movement finally bends the concrete river of convention toward a sustainable future.
Tyler Westerman is a neophyte of sustainable construction. He is an apprentice plaster worker, an aspiring building scientist, and a contributing editor to The Last Straw

THE LAST STRAW
The Alternative Journal of Design and Construction for Dirtbags and Dreamers
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