Hempcrete Goes Mainstream: What Still Has to Change

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Imagine you are a builder who has spent years learning about hempcrete. You know its insulating power, its breathability, and its low environmental footprint. You finally have a client who wants to build with it, and you feel ready. Then you walk into your local building department, place your plans on the counter, and watch the official's face go blank. There is no checkbox for hempcrete. There is no familiar section in the codebook. You are about to spend the next six months explaining a material that grows in a field to people who think only in terms of lumber and drywall. For most of the last decade, that was the reality for anyone in the United States who wanted to build with this remarkable plant-based material. Every project was a fight for approval, a one off variance that depended entirely on the mood and curiosity of a local inspector. That finally started to change in 2024, when the International Code Council added a dedicated appendix for hempcrete to the residential code. It felt like a victory, and in many ways it was. But if you scratch the surface, the picture gets complicated fast. That appendix only covers single family homes. Commercial buildings, apartments, and offices are still left out in the cold. And even where the code now exists, the real barriers are no longer about legality. They are about manufacturing capacity, supply chains, and a construction industry that moves at a glacial pace. This is the story of hempcrete in 2026, a material caught between genuine promise and the grinding, unglamorous work of actually building things at scale. It is a story about hope, yes, but more than that, it is a story about patience.

The Code Finally Caught Up -- Partially

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For most of the last decade, anyone wanting to build with hempcrete in the United States had to make a case for it from scratch, every single time. There was no code section to point to, no pre-approved assembly, nothing a building official could stamp and move on from. That changed, at least on paper, in 2024, when the International Code Council folded Appendix BL -- Hemp Lime (Hempcrete) Construction -- into the International Residential Code. It's the first time hempcrete has had a dedicated appendix in the model code that most US jurisdictions use as their starting template, and it didn't happen by accident. The US Hemp Building Association spent years lobbying, drafting, and resubmitting language through the ICC's public comment process, leaning on the ASTM International standard for hempcrete insulation released in 2022 -- the first time the material had a recognized testing standard to point building officials toward at all. Without that ASTM baseline, there was no way to write enforceable code language around fire performance, moisture behavior, or thermal values, so the 2022 standard was the precondition for everything that followed.

USHBA president Henry Gage Jr. described the appendix's adoption as a shift toward the mainstream, and that's a fair read of what it represents symbolically. But the phrase that matters more in practice is that it's an appendix, not a mandatory chapter. The IRC works on a three-year revision cycle, and individual states and municipalities decide which appendices they actually adopt when they bring a new edition of the code online locally. Getting into the 2024 IRC guarantees that Appendix BL exists as ready-made language sitting in a document that code officials already recognize. It does not guarantee that a single one of them will turn it on. That distinction is the whole story right now -- national code inclusion was the hard first step, but it converts to real permitting power only jurisdiction by jurisdiction, and that process is just getting started.

Austin, Texas holds the distinction of being first: the city put Appendix BL into effect on July 10, 2025, giving local builders and permitting staff an actual adopted pathway rather than a case-by-case argument. Minnesota is running the same process on a slower, more procedural track. Its technical advisory group and codes council worked the appendix through for the state's next residential code cycle in 2025, and advocates reportedly had to appear before the advisory board twice, each time with substantial revisions, before getting sign-off. Supplemental city-level guidance in Minnesota isn't expected to be finalized until sometime in 2026. Two states, two timelines, and neither one automatic.

Everywhere else, builders are still where they've always been: leaning on IRC Section R104.11, the Alternative Materials, Design and Methods of Construction provision that lets a building official approve a non-standard material on a case-by-case basis. That means assembling ASTM test data, fire ratings, and structural calculations project by project, and hoping the official reviewing them is willing to engage with an unfamiliar submittal package at all.

The Commercial Gap: Homes Are Covered, Offices and Apartments Aren't

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Walk into any hempcrete project that's made the rounds on architecture blogs in the last few years and you'll notice a pattern: it's a custom home in the Blue Ridge Mountains, a straw-and-hemp cottage in Vermont, an owner-built retirement house outside Asheville. What you won't find is a mid-rise apartment building in Denver or a corporate office park in Austin. That's not an accident of taste or marketing. It's a direct consequence of which code book hempcrete actually lives in.

Appendix BL, the hempcrete provision added to the 2021 International Residential Code, is scoped exactly the way its parent document is scoped: single-family homes and buildings with a limited number of dwelling units, typically capped at the same threshold the IRC itself uses for duplexes and small multi-family structures. It was never written to cover anything larger. Commercial construction -- office towers, hotels, apartment complexes above that unit threshold, retail buildings, schools -- runs through an entirely separate document, the International Building Code, published by the same organization, the International Code Council, but governed by its own committees and its own approval track. And in the IBC, as of now, hempcrete doesn't appear at all. Not as a prescriptive method, not as an alternative material with defined pathways -- it's simply absent.

The U.S. Hemp Building Association, which did the multi-year work of getting Appendix BL adopted in the first place, is now turning its attention to the IBC. That effort is still in early stages, and if the residential fight is any guide, it will not move quickly. The ASTM standard underpinning hempcrete's material properties was finalized in 2022; the IRC appendix built on that standard wasn't adopted until the 2024 code cycle; and cities and counties are still, one by one, incorporating that 2024 IRC into their local permitting rules, a process that typically lags national code adoption by one to three years depending on the jurisdiction. There's no reason to expect the IBC process to compress that timeline -- commercial code committees tend to be more conservative than residential ones, given the higher occupancy loads and liability at stake, so a realistic window is more years, not months.

Until that changes, a developer who wants to build a hempcrete office building or apartment complex is stuck exactly where residential builders were before 2021: filing for approval as an alternative material under IBC Section 104.11, which means commissioning engineering reports, fire and structural testing data, and often a full peer review, project by project, city by city. That's a manageable lift for a single owner-builder willing to spend a year on paperwork for one house. It's a much harder sell to a commercial lender or a developer answerable to investors, where the same documentation burden lands on a building with far more square footage, far more occupants, and far more exposure if an inspector or insurer balks midway through. That asymmetry -- low stakes and high patience tolerance on the residential side, high stakes and low patience tolerance on the commercial side -- is the real reason hempcrete's visible footprint is still overwhelmingly custom homes rather than the apartment and office stock that would actually move the needle on volume.

Why Hempcrete Still Needs a Skeleton

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Walk onto a hempcrete job site and the first thing you'll notice is the timber. Lots of it. Studs, posts, sometimes a full post-and-beam skeleton going up before a single batch of hemp hurd gets mixed with lime binder. That's not an aesthetic choice or a nod to rustic charm -- it's a structural requirement written into every code pathway that currently recognizes hempcrete as a building material. Erica Stark, executive director of the National Hemp Association, has been blunt about this with builders who come to her expecting hempcrete to behave like poured concrete: it doesn't, and under the codes as they exist today, it legally can't.

Hempcrete is classified as a non-load-bearing material. That's not a marketing footnote, it's the operative fact that shapes every project using it in the US and most of Europe right now. The material goes in as infill -- packed or sprayed into cavities around a structural frame, providing insulation, thermal mass, and moisture regulation, but contributing essentially nothing to the building's ability to hold itself up. Conceptually it sits much closer to straw-bale construction or structural insulated panels (SIPs) than to concrete, even though the name invites the comparison to concrete constantly. A straw-bale wall doesn't hold up a roof either; something else does that job while the bale does the insulating. Hempcrete, as currently coded, works the same way.

That classification puts a hard ceiling on what hempcrete can realistically do in the next few years. Multi-story apartment blocks, anything with long structural spans, tall commercial buildings -- those typologies need load paths that hempcrete in its current form isn't engineered or tested to provide. What you get instead is a strong fit for single-family homes, low-rise residential, and accessory structures, where a timber or engineered-lumber frame carries the loads and hempcrete fills the envelope. That's a real market, but it's a fraction of the addressable construction industry, and it's why hempcrete keeps showing up in demonstration homes and boutique builds rather than mid-rise infill projects in cities that badly need more housing stock.

This is exactly the ceiling that outfits like Renewabuild Great Plains are betting they can push through with structural hempcrete block products -- an attempt worth examining on its own, because it's effectively wagering that enough compressive-strength testing data can move the material out of the infill category entirely.

Until that data exists at scale and gets absorbed into code bodies like the International Code Council, engineers stay stuck doing double work: running conventional load calculations for a timber or steel frame exactly as they would on any other project, then layering hempcrete's thermal and moisture performance on top as a separate design track. That duplication adds real line items to a project budget -- engineering hours, structural review, sometimes a frame over-designed for redundancy because nobody wants a liability exposure on an unfamiliar assembly. It's the part of hempcrete's story that promotional material tends to skip past entirely.

The Bottleneck Isn't Legal, It's Industrial

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Ask anyone who has actually tried to buy hemp hurd at scale in the US, and the story is the same one Stark tells: for most of the last decade, if you wanted processed hemp fiber for building material, you were buying it from Europe. France, the Netherlands, and a handful of other countries had decades of industrial hemp processing infrastructure that the US, thanks to the 2018 Farm Bill's late arrival, simply didn't have. That meant paying to ship a bulky, low-density agricultural byproduct across an ocean -- a cost structure that makes sense for a boutique insulation product sold to a handful of green-building enthusiasts, and makes no sense at all for a construction material meant to compete with concrete block or dimensional lumber on price.

The domestic picture has improved, but not nearly enough to matter yet. Decortication -- the mechanical process that separates hemp stalks into bast fiber and hurd -- now happens at various points across the Midwest and elsewhere, but most of those facilities are running at roughly five tons of hemp per hour. That sounds like a lot until you run the math on what a single mid-sized residential subdivision would consume in hempcrete block, let alone a regional construction market. Five tons an hour is a rate built for niche markets: textiles, animal bedding, some paper pulp, small-batch building material. It is not a rate that supports hempcrete as a mainstream alternative to CMU block or SIPs panels at anything like competitive pricing.

Stark's argument for why this matters goes beyond raw throughput -- it's about geography. Hurd is bulky, low in density, and expensive to move relative to its value, which means decortication and panel manufacturing ideally need to sit within about fifty miles of the fields where the hemp is grown. That's a fundamentally different industrial model than, say, steel or cement, where the raw material can travel a long way before it eats the margin. It's closer to how sugar beet processing or corn ethanol plants get sited -- clustered near the crop, because the crop itself is uneconomical to haul far in its raw form. Any serious hempcrete supply chain in the US is going to look like a scattering of regional processing hubs tied to local hemp acreage, not a handful of national plants shipping hurd cross-country.

That's the frame for why Renewabuild Great Plains matters as a test case rather than just a company announcement. Co-founded by Ken Meyer of Complete Hemp Processing, the venture is building what's being billed as the first US-licensed manufacturing facility for structural hempcrete blocks, sited in Rock Valley, Iowa, and using technology licensed from Alberta-based Just BioFiber/Renewabuild Field to Form. The facility is scheduled to receive its manufacturing equipment in December 2026 or January 2027. At full three-shift capacity, the projected output is over 900,000 structural hempcrete blocks a year -- a number worth watching not because it's guaranteed to hit, but because it's the first concrete benchmark for whether regional, crop-adjacent processing can actually deliver industrial volume rather than boutique volume.

What the Market Numbers Actually Say -- and Don't

Hempcrete's market value is projected to grow substantially, more than doubling from an estimated $1.2 billion globally in 2026 to $2.7 billion by 2033, with North America alone expected to reach $3.5 billion by that year.

Pull up three different market research reports on hempcrete and you'll get three different futures. One widely cited projection puts the global hempcrete market at roughly $1.2 billion in 2026, climbing to about $2.7 billion by 2033 -- a 12.4% compound annual growth rate that reads as steady, unspectacular, the kind of curve you'd expect from a niche building material slowly finding its footing. Another report, focused just on North America, projects a 25.3% CAGR pushing the regional market to $3.5 billion by that same year. Those two numbers aren't measuring slightly different things -- they're telling almost incompatible stories about how fast this material is supposed to scale, and the gap between them is the most honest data point in the whole sector.

That spread exists because hempcrete is still small enough, and undertracked enough, that forecasting firms are working from thin datasets and have to make big assumptions about adoption curves, regional building codes, and how much of the projected growth comes from residential retrofits versus new commercial construction. When a market is mature -- lumber, concrete, drywall -- analysts converge because there's decades of consistent transaction data to anchor them. When a market is this young, a forecast is really a bet on which trend lines get extrapolated and how aggressively. Treat both numbers as directionally useful -- the sector is growing -- and specifically unreliable. Anyone citing a hempcrete market figure to three significant digits is overstating what's actually knowable right now.

The barriers behind that uncertainty show up consistently across nearly every industry survey and trade report: contractors and builders frequently report not knowing how to price, mix, or install hempcrete correctly, and that unfamiliarity translates directly into higher quoted labor costs even before material costs are factored in. Hempcrete itself typically costs more upfront than conventional stick-frame insulation and drywall, and the payback -- lower heating and cooling bills from its thermal mass and vapor permeability -- accrues over years, which is a hard sell to a homeowner or developer comparing bids today. This is the same adoption friction that slowed structural insulated panels and cross-laminated timber in their early years in the U.S., and both of those took the better part of a decade to move from novelty to spec-sheet default even after codes cleared the way.

The UK is the cautionary tale worth sitting with. Hempcrete has been used there in niche renovation and self-build projects for over a decade, with a real track record and enough completed structures to demonstrate durability. It still hasn't crossed into mainstream commercial housing or large-scale infrastructure. That's a useful corrective to the assumption that regulatory acceptance alone unlocks a market -- Britain had years of practical familiarity and still stayed niche, which suggests awareness and cost, not just code language, are the deciding variables.

The counter-case for the U.S. is that it may have something the UK never assembled: code inclusion arriving alongside a dedicated domestic manufacturing base, IF a facility like Iowa's actually delivers consistent hurd supply at scale. That combination -- codified pathway plus reliable feedstock -- is a genuinely different starting position than the UK had. Whether it's enough to avoid a similar plateau is a projection, not a certainty.

The Realistic Sequence From Here

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Straw-bale construction is the closest analog we have, and its timeline is sobering. The first modern straw-bale structures went up in Nebraska in the 1990s, building officials spent most of a decade treating each project as a one-off variance, and it wasn't until 2015 that straw-bale finally got its own appendix in the International Residential Code. That's roughly twenty years from scattered pilot builds to a nationally codified path, and even then adoption remained spotty -- plenty of jurisdictions still haven't formally pulled Appendix S into their local code. Hempcrete is starting from a better position: Appendix BL landed in the 2021 IRC without two decades of ad hoc precedent behind it, largely because straw-bale, rammed earth, and other alternative assemblies had already worn down building officials' resistance to non-standard wall systems. But having the appendix written and having it adopted city by city are different problems, and the straw-bale record suggests the second one eats years even when the first one is solved.

Over the next one to three years, expect the visible progress to be almost entirely municipal. More cities will do what Austin did -- formally adopt Appendix BL as a local amendment rather than waiting for a state-level mandate -- because that's a low-lift regulatory action a city council or building department can push through without state legislative involvement. Watch for advocacy aimed at the International Code Council itself, pushing hempcrete assemblies into the International Building Code so commercial and multifamily projects have a path, not just single-family homes under the IRC. This is also the window where the Iowa decortication and hempcrete-block facility either proves out or exposes the regional-manufacturing thesis: if it can source Midwest hemp hurd, process it locally, and land finished material at a price competitive with SIPs or ICF within trucking distance of the plant, that becomes the template other regions copy. If it struggles with throughput or feedstock supply, expect the timeline to stretch.

Three to seven years out, the interesting shift would be structural, not geographic: proposals to move certain hempcrete wall assemblies beyond strictly non-load-bearing status. This is exactly the pattern rammed earth and structural insulated panels followed -- initial code acceptance came with heavy restrictions, then engineering test data accumulated project by project until code bodies were willing to expand the scope. It requires several years of monitored builds generating compressive strength and moisture performance data under real climate exposure, not lab conditions. That data doesn't exist in sufficient volume yet.

The realistic threats to this timeline are unglamorous: decortication capacity stays thin and prices stay uncompetitive with conventional framing, contractor training pipelines lag behind code availability so licensed installers remain scarce even where the code permits the work, and IBC commercial adoption drags out longer than the IRC fight did, because commercial liability exposure makes code bodies more conservative. None of this needs a legislative act the way rescheduling does -- it's an industrial-capacity and codes problem, and those move on their own slow, technical clock.

So where does that leave the architect sketching her first hempcrete project, the contractor pricing out a job, or the homeowner dreaming of a healthier, more sustainable house? In a place that feels a lot like a waiting room. The code is finally written, and that is no small thing. Appendix BL exists because advocates spent years showing up at hearings, submitting test data, and making the case that this material deserves a place at the table. Austin and Minnesota are proving that local adoption is possible. The Iowa block facility is a genuine milestone, the first real test of whether the United States can process hemp hurd at industrial scale rather than importing it from Europe. These are real steps forward, not just press releases.

But if there is one lesson from the long, slow rise of straw bale construction, it is that code acceptance is only the beginning of the journey, not the destination. The next few years will not be defined by dramatic announcements. They will be defined by municipal votes, one by one. By contractors learning to mix lime and hurd without guessing. By engineers gathering compressive strength data on real buildings in real climates. By a decortication plant in Iowa proving it can actually deliver hundreds of thousands of blocks a year. That is the unglamorous, essential work that turns a novelty into a standard.

For now, hempcrete remains what it has always been, a deeply promising material that asks more of its builders than a bag of fiberglass insulation or a stack of concrete blocks. It asks for a willingness to learn, to advocate, and to wait. But for the people who care about building differently, who see the carbon footprint of cement and the waste of conventional construction, that waiting feels less like a burden and more like a responsibility. The foundation has been laid, literally and figuratively. Now comes the slower, quieter work of filling it in, one wall, one permit, one city at a time.

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