Why an overlooked farm byproduct may be Canada’s most scalable low-carbon building solution
Photo: Hundred Year Materials
Every year, farms across the country leave behind a residue so abundant that millions of tonnes never find a meaningful use. Yet this so-called waste holds the potential to unlock new economic opportunities for builders, manufacturers, and farmers, create rural manufacturing jobs, make our homes healthier, and turn the built environment from a carbon problem into a carbon sink.
A growing roster of bio-based materials – from mycelium and hemp to wood fibre and cellulose – are emerging as ways to cut embodied carbon in buildings, but in Canada none but straw combine performance, availability, affordability, and scalability, say experts and straw innovators interviewed for this article. Straw stands apart in Canada because it is already produced at massive scale, costs little, performs well under fire, contains no toxic chemicals, and requires minimal processing or new infrastructure to turn into insulation, they say.
“There’s not many other materials that are that adaptable, that you can use in so many different contexts, and we grow millions of tonnes of it a year that we don’t do anything with,” said Chris Magwood, long-time Ontario-based straw-home builder and manager of carbon-free buildings at RMI.
Across Canada, a new generation of builders and manufacturers are transforming straw from a seasonally constrained, labour-intensive building tradition into a high-performance, carbon-negative, drop-in building solution. As European products enter the market and Canadian innovators push straw into blown, batt, and panelized formats, the material may shed its alternative label and emerge as a serious contender to help decarbonize our buildings.
Despite a long history of insulating homes – think straw-bale construction – the industry has failed to take root. After years of false starts and failed businesses, will straw grow-up as a viable commercial solution and be ready for harvest at scale?
Straw is an Abundant Carbon Negative, Resilient By-product
Straw is the dry stem left after harvesting grains like wheat, barley, and oats. The carbon in straw was already pulled from the atmosphere as the plant grew and stays locked in the straw for as long as the straw exists. Its structure traps air for effective insulation, in a densepack or baled form it chars rather than ignites under flame, and it does not rot or lose performance easily. While certain flame-retardant chemicals used in spray foam insulation can remain detectable in indoor air for years after installation, naturally flame retardant, straw-based insulation does not carry this risk.
Straw is essentially a byproduct because it’s difficult for microbes to break down, so it doesn’t function well as a soil amendment and farmers remove most of it from the field, said straw-bale and high-performance homebuilder Ben Polley.
“These are all reasons that actually make it an ideal building material,” said Polley, President (and co-founder) of Evolve Builders in Guelph. “Our best carbon performing projects have all been ones that involve straw.”
Photo: Harvest Homes/Evolve Builders Group Inc.
Straw is also extremely available across the Prairies from BC to Quebec. As a snap shot, the Canadian Prairies generate roughly 37 million tonnes of straw, of which more than 15 million tonnes remain available after meeting soil and livestock needs.
“If you add up all the straw, that is a byproduct of farming every year in Canada and If you use a third of it, you could insulate every building that’s constructed in Canada every year,” said Sam Kondratski, founder and CEO of Savick, an Alberta-based prefab builder using straw as insulation.
Straw could be a leading part of a revolution in bio-based materials that could turn buildings from a major source of carbon pollution to become a carbon sink.
“It wouldn’t be hard to flip the [U.S.] home building sector from emitting about 50 million tonnes of carbon a year to storing 50 million tonnes,” said Magwood.
Magwood’s recent RMI report Building with Biomass: A New American Harvest maps a broad set of biogenic building products upcycling underused biomass such as straw, hemp, wood fiber, agricultural residues, mycelium, seaweed, and biochar. The report concludes that building with bio-based materials, with straw as the leading feedstock, could unlock $79 billion in domestic manufacturing, create roughly 42,000 rural manufacturing jobs, and store up to 100 million tonnes of CO₂e in new housing under a low-adoption scenario by 2050.
“In Canada and in the US, we’ve got a lot of rural communities with major employment problems. We could be paying farmers and foresters for their residues and then processing those into building products in the region where they’re made,” said Magwood.
Other Bio-alternatives Have Higher Barriers
In the alternative bio-based materials ecosystem in Canada, hemp, mycelium and wood fibre are all other potential sources of new bio-based insulation materials. Beyond its abundance, straw’s advantage is that it requires almost no processing infrastructure and added energy.
Source: RMI
After exploring developing a wood fibre-based insulation, straw-insulation innovator Garrett Johnson, the founder and CEO of Hundred Year Materials, reached the conclusion that wood fibre insulation, despite its biogenic benefits, often carries high upfront energy and infrastructure costs. High-performance wood fibre insulation requires specialized high-consistency refiners and precisely sized wood chips, and is not made from wood waste. Manufacturers typically use virgin pulpwood that must be debarked, chipped, steamed under pressure, and mechanically refined, making the process energy-intensive, said Johnson.
“A lot of the wood fiber installations, they actually have the same or higher upfront energy emissions intensity as the polystyrene installations they’re replacing,” said Johnson.
While low-carbon wood cellulose insulation used to be primarily made from recycled newspaper, offering a new pathway for an abundant waste product, the death of print media has upended the material flow, resulting in virgin newsprint feeding the cellulose market, said Johnson.
Hemp insulation, meanwhile, has struggled to gain traction in Canada because it is a purpose-grown crop that requires specialized harvesting and processing infrastructure, making it far more expensive and difficult to scale than agricultural residues like straw, said Johnson.
Mycelium-based materials (i.e., the underground connector of mushrooms) show significant promise, but Magwood notes that scaling them requires manufacturing conditions closer to food processing than construction, including clean-room environments to prevent contamination, creating high capital barriers that have slowed their commercial adoption.
“It doesn’t take an insane investment to make something practical out of straw,” said Magwood.
The opportunity for straw-based building materials has never been clearer, but technical logic is not enough to guarantee market success.
Savick straw wall panel demo
Why is Straw Not Mainstream Today?
Straw in construction isn’t new. Straw has been used in construction for thousands of years and straw-bale building emerged in the late nineteenth century. Given its long history, strong performance, and abundance, why has straw remained a fringe material in modern construction rather than becoming a mainstream building solution?
With straw bale construction, builders stack bales “like giant Lego” and then finish with hand-applied plaster. The plaster is temperature dependent and seasonally constrained, which has limited a wider adoption of the building technique, said Polley.
“If we can prefabricate them off site in controlled conditions, then that particular issue goes away,” said Polley.
From Magwood’s perspective, straw never scaled because there hasn’t been a driving force, no proprietary product, patent, or dominant firm. There has been no clear actor with an incentive to fund testing, code approvals, and market development.
“Straw has been open source and free from the get go; there’s no Big Straw out there,” said Magwood.
Kondratski says adoption hinges on customer confidence that straw can deliver a high-performance, healthy home, not just meet baseline code requirements.
“That is the most challenging but most rewarding piece of it,” said Kondratski.
Straw, like other sustainable and innovative materials, struggles to gain acceptance in an industry shaped by risk aversion and status quo bias, where unfamiliar materials that fall outside prescriptive codes are perceived as experimental, difficult to insure, and incompatible with a building culture that prioritizes speed and certainty over long-term performance.
Photo: Savick
Innovators Shifting the Landscape
Seeing both the potential of straw and the structural reasons it never scaled, Polley is exploring how dense-packed straw and other agricultural fibres can move from one-off projects into standardized products using off-site construction.
“We are actually readying ourselves to spin it off as a separate operating entity,” said Polley.
Drawing on his experience with straw construction and navigating alternative solutions pathways in the building code, Polley has directly intersected with the efforts of Johnson, who is developing a new generation of straw-based insulation products, including rigid boards, batts, and blown formats.
“[Straw] has the opportunity to democratize bio-based building materials to have a price point that becomes attractive to the big builders,” said Johnson.
Johnson is currently in the product validation and testing phase, generating the data needed to navigate regulatory approvals.
Out west, Kondratski of Savick is taking a deliberately cautious approach shaped by past failures in Alberta’s straw-processing sector. He notes that several multi-million-dollar attempts to commercialize straw products collapsed after assuming that supply chains would resolve themselves with enough capital. Instead, Savick has focused on starting small, aligning production with what it can deliver, and not over promising.
Straw’s potential, in the end, is that Canada already produces it at scale, moves it through rural supply chains, and knows how it behaves in buildings. What has been missing is the slow, unglamorous work of turning a residue into a product: testing it, standardizing it, financing it, insuring it, and persuading cautious homeowners and builders to trust it. If straw succeeds, it will be because it fits the constraints of how buildings are made while solving problems of carbon, health, and performance along the way.
