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Biofiber Hempcrete Blocks for zero carbon Trent Forensics Facility

Feb 11, 2021 

Trent University has a goal to store more carbon in the building materials of their new Forensics Facility than was emitted in making the materials. In order to offset the inevitable emissions from harvesting and manufacturing materials it is necessary to use biogenic (plant-based) materials that store carbon in the material.

Hemp is the plant-based material of choice for this project. We chose two hemp-based materials for the Trent Forensics facility: Just Biofiber hemp blocks to be the load-bearing walls of the building and NatureFibres hemp batts to insulate the stud wall cavities. This post will focus on the Just Biofiber blocks.

Just Biofiber hempcrete blocks are a new product being manufactured in Alberta, Canada. The blocks consist of a plastic frame around which hempcrete is cast and cured. The blocks look and act much like large Lego blocks, with the eight posts on the top of a block fitting into holes in the bottom of the block above.

The Just Biofiber blocks provide enough load-bearing capacity in the plastic frames to be the structural wall for the building, and offer R-21 of thermal performance. A mortar made from lime and chopped flax is used to seal between each block and glue is applied to the plastic posts to attach the blocks together.

We were excited to work with Just Biofiber hempcrete blocks, having watched the company go through initial development and testing very closely. In practice, we found the system had a few key flaws. Firstly, the glue that is required is smelly, toxic and messy. Our crew truly despised working with the glue. Secondly, the Lego-like fit between the blocks made for a fussy installation as the tolerance is around 1/8-inch and if the foundation isn’t perfectly level a lot of work is required to ensure the blocks actually fit. A lot of dry-stacking is required to ensure a fit, and shimming was constant throughout the process. Finally, there are threaded rods required within the blocks and these were fussy and slow to install. The relatively low thermal performance of the blocks required us to add a frame wall with more insulation to meet our R-40 target.

We loved working with a hempcrete product that didn’t require site mixing or a lengthy drying process, but feel that the Just Biofiber hempcrete blocks need more development before they are a cost-competitive and easy-to-install system. We hope to see Just Biofiber continue to innovate and improve their system and look forward to a chance to work with the product again in an updated form.

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Hempcrete Submitted for Certification in US Building Codes

The 6,000 sq. ft Cape Cod Hemp House, built in 2021-2022, is the largest hempcrete-insulated structure built in the US last year. Photo courtesy of Mpactful Ventures

The professional association representing the US hemp building industry moved forward to certify hemp and lime (hempcrete) insulation in US building codes this month.

Hempcrete was submitted as an appendix in the International Residential Codes on Jan. 10 by the US Hemp Building Foundation, the non-profit arm of the US Hemp Building Association.

The idea is to give U.S. building permitting departments a familiarity with the material, which is new to the United States after hemp was legalized under the 2018 Farm Bill. 

“These documents will show a pathway for using hempcrete as a building material,” USHBA President Jacob Waddell told HempBuildMag. “The goal is to allow you to build with hempcrete without needing an alternative material variance,” he added. 

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An international committee of hemp building experts and advocates prepared the paperwork to submit to the International Code Council. IRC code experts will evaluate the paperwork in March and again in September to enshrine hemp + lime as an approved natural building material. 

Eventually, inclusion in the IRC should “allow for hempcrete to be accessible to the standard person to construct with it,” Waddell said. 

Hempcrete, a non-structural insulation made of hemp hurd (shiv) and lime binder, provides a superior insulation product when installed up to 1 foot thick in wall assemblies. The material is vapor-permeable, thermally regulating, fire resistant and and repels mold and pests. Hempcrete insulation is carbon negative due to the large amounts of carbon sequestered by the hemp plant via photosynthesis while growing.

Used widely in Europe

The US building industry has some catching up to do when it comes to the international use of hemp in building materials.

Hempcrete has been employed as a carbon-negative insulation for 30 years in Europe, as an insulating construction material for large department stores in the United Kingdom and multistory residential buildings and public facilities in France.

Thirty-unit hempcrete apartment building in Paris. Photo courtesy of North by Northwest Architectes.

Patchwork of US building departments

Right now in the United States, builders, engineers and architects who want to use hempcrete must gain approval project-by-project in the absence of an overarching national code to point to, said Texas-based developer Ray Kaderli, of the Hemp Build Network.

Kaderli’s company was just permitted by the city of San Antonio to build a hempcrete-insulated three-bedroom/two-bath 1,300 sq. ft. home. 

Kaderli, a member of USHBA, praised the organization for moving forward with certification for hempcrete. 

“With a new industry there are many things to do,” Kaderli said in an email. “This was one of the most important first steps. I’m grateful [USHBA] had the insight and discipline to focus in this direction.”

The certification process also leads the way to apply to certify hempcrete in the International Commercial Building Codes for commercial buildings in 2024, when the next application process begins, USHBA president Waddell said. 

The material still needs to pass various ASTM fire tests as well as tests for structural bracing, Waddell said, for which the foundation will continue to raise funds. 

Straw bale builders paved the way

USHBA hired engineering and natural building consultants, including two straw bale construction pioneers who helped get straw bale construction certified in the US residential building codes in the early 2000s. 

Right now, the application submitted to the IRC only includes one-story structures to be insulated with hempcrete wall assemblies without extra engineering. This is a start that will be built upon to expand hempcrete’s role in the building codes, as more data and research is submitted and approved, Waddell said. 

“Submitting to the IRC is just the first step in a very long process to get hempcrete where we’re able to use it more readily,” Waddell said. 

The USHBA has about 200 active members and raised about $50,000 through its foundation for certification expenses and a series of other projects, including workforce development and creating educational materials, Waddell said.

The organization will host a members-only online event on Saturday, Jan. 30, where more information about the IRC certification will be shared.

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6,000-sq. ft hemp home befuddled permit officials 

The Massachusetts building permit official who approved one of last year’s largest hempcrete projects built on US soil last year, was initially confused at the rough inspection of the Cape Cod Hemp House, said Mary Dempsey, of Mpactful Ventures. 

“The building inspector took one look and said, ‘Wait a minute where’s your plywood?’ Then he muttered, ‘I gotta go study these plans better,’” she told HempBuildMag.

Even though the Cape Cod Hemp House relied on engineering approval and didn’t have difficulty getting a permit, Dempsey said including hempcrete in the IRC codes will help local building permitting authorities better understand how it works and what it can and cannot do. Mpactful Ventures and Dempsey helped steer the USHBA study group to gather the paperwork and research together to submit to the IRC. 

“People from all over the world were helping by reading this [document] to hopefully move an entire industry forward,” Dempsey said. “I’m really proud to have been part of it.”

Jean Lotus is editor and publisher of HempBuild Magazine.

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Pot Porsches and Hempcrete are here

From stalled legislation to falling stock prices, cannabis didn’t have the greatest year. But investors are finding something to be optimistic about heading into 2022: industrial hemp.

Demand is poised to rise for hemp — the staid sister to the mood-altering forms of cannabis — as it’s increasingly adopted for a wide range of uses, including concrete blocks, clothing and even car parts. The shift is driven by environmental incentives such as carbon caps and single-use plastic bans, which are making some natural materials preferable to those made from petrochemicals.

“Industrial hemp is the biggest opportunity in the cannabis sector as a whole,” said Mina Mishrikey, a partner at Merida Capital Partners. His firm has invested around 90% to 95% of its $500 million in assets under management in cannabis businesses centered around THC, the psychoactive ingredient in marijuana, but aims to make more investments in industrial hemp, Mishrikey told me.

Hemp could use the boost after the market struggled to capitalize on the hype following the 2018 farm bill, which legalized hemp and led to over-planting when not enough companies were ready to create end products. In 2021, the number of acres of hemp planted fell to 33,844 from 70,530 a year earlier and 465,787 in 2019 according to New Frontier Data.

Adding to the challenges, the U.S. Food and Drug Administration recently refused to regulate one of hemp's best-known products — CBD, or cannabidiol — as a dietary ingredient, casting a specter of uncertainty over the otherwise booming market for creams, tinctures and gummies.

As a material, hemp remains more expensive than alternatives that come from petrochemicals. But India, Canada, Germany and South Africa are among the countries cracking down on plastics in 2022, making alternatives more economical. Meanwhile, pressure to shift from oil and gas to renewable industries is increasing and carbon credits are becoming more valuable — and that’s an area where hemp has an advantage.

Mishrikey sees the plant’s ability to capture carbon while it’s growing, and its ability to use less water than cotton, as key factors that help it disrupt a range of products. Just one category of industrial hemp alone — precast concrete — is worth around $20 billion, roughly the same size as the current U.S. legal marijuana market, he pointed out.

His fund’s investments include Canadian Rockies Hemp Corp., based in Bruderheim, Alberta, which processes hemp for use in textiles, pulp and paper, animal bedding, rope, composites and automobile components, according to its website. Another is Bast Fibre Technologies Inc., based in Victoria, British Columbia, which has a processing technology to make nonwoven fabrics with natural fibers including hemp. That could be helpful for the booming market in wipes, which are ripe for disruption due to the sewer-clogging gobs known as fatbergs.

Hemp could play a role in many categories: plastics, textiles, papers, building materials, protein for humans and animals, and concrete of all forms. Some of the more innovative applications include hempcrete, where hemp fibers are infused in the mortar, and a Porsche car with some components made of hemp. Some see hemp as a viable alternative to almost anything made from petrochemicals, due to the properties of its cellulose fibers.

The U.S. will have some catching up to do: China is the leading grower of hemp and is  tiptoeing into the CBD market, starting with Hong Kong. The plants also require different agricultural and processing techniques compared to other forms of cannabis, meaning the supply chain will have to be built out from scratch. Processing the plant's tough fibers, called decortication, is an arduous practice that takes heavy machinery and has created something of a bottleneck.

That bottleneck is about to get some help from a $500 million impact fund by rePlant Hemp Advisors, launched in early November by Geoff Whaling, co-founder of Collective Growth Corp., and others including Michael Woods, former chief executive officer and chief operating officer of Rothschild & Co. Asset Management U.S. The fund plans to help develop U.S. infrastructure to process hemp and improve the supply chain, focusing on hemp for food and fiber.

“I probably have a dozen companies call me a week” about using hemp in their products, Whaling said, citing brands like Chobani, Wrangler jeans and Tesla.

“They all want to know where they can get 100 tons of fiber a year, and the answer, at this point, is nowhere,” he said. “No major manufacturer will sign unless there's a two-year supply in a warehouse.”

But slowly, that’s changing.

“We're seeing more countries advancing and mandating use of sustainable fibers, more auto companies adopting natural fiber solutions,” Whaling said. “It really is an industrial hemp revolution.”

Number of the week 

16.6% The compound annual growth rate of the legal U.S. cannabis market from 2020 to 2025, as estimated by New Frontier Data in their 2021 Year in Review report.

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As Lumber Prices Surge, Hemp Blocks Get a Closer Look

By Jean Lotus

The cost of U.S. construction timber is skyrocketing, and a national concern is growing for the  carbon emitted by the construction industry. As homebuilders look for solutions, the nation’s small-but-growing number of hemp builders wonder if building with hemp will finally break through into the mainstream construction consciousness. 

Load-bearing hempcrete wall systems are getting more attention as lumber costs for frame walls has spiked. Photo courtesy of  HempBLOCKUSA
Load-bearing hempcrete wall systems are getting more attention as lumber costs for frame walls has spiked. Photo courtesy of HempBLOCKUSA

The cost of framing lumber, OSB plywood and other wood building materials are adding an average of $36,000 to the cost of a new build, an April study showed — and costs have kept rising.  

As a result, homebuilding solutions that don’t require framing timber, or need less of it, are getting a second look. One solution is the hemp-lime block.

The U.S. construction industry is notoriously resistant to change and innovation, frustrating those  who want to introduce hemp building to the United States, as it has been used for the past 30 years in Europe. 

But ‘hempcrete’ blocks are being noticed because they have been used in European builds for decades, and provide a green, carbon-sequestering, insulative wall solution. 

“We have been working to decarbonize the construction sector for 10 years now and we remain 100% convinced that the hemp block has a crucial role to play,” Charlotte De Bellefroid, spokesperson for Belgium-based IsoHemp, wrote in an email to Hemp Build Mag. 

The company manufactures 1 million hemp blocks per year and will increase production to 5 million blocks per year with a new robotic factory to keep up with demand. 

A new Joe Biden administration focus on reducing carbon in the construction industry, has focused on more efficient buildings, but carbon-sequestering industrial hemp could possibly  have a prominent place in the discussion. 

It will be “impossible” to halve U.S. greenhouse gas emissions by 2030 “without rapid decarbonization of the building sector,” Alliance to Save Energy (ASE) President Paula Glover said in a statement last week. 

Light weight, quick to assemble

Precast hemp blocks, made with chopped hemp hurd and lime binder are much lighter than concrete blocks. The blocks can be quickly assembled and provide insulation rates up to R70. Uniform-density blocks are easy to transport to a worksite, and are pre-cured, saving drying time compared to hand-cast “in situ” or spray applied hempcrete construction. 

Walls made with hempcrete blocks are fireproof, mold proof, pest proof and long-lasting compared to timber-framed homes, which can be constructed of poor quality materials.

Load-bearing systems

By themselves, unlike concrete cinder blocks, hempcrete blocks are not loadbearing, so they can’t be completely swapped out for timber home framing.

However, IsoHemp and others, including the Vicat Group in France, have developed an inner steel post-and-beam support system that can replace timber framing in the block walls.

HempBLOCK USA, a new Australian hemp block supplier, licenses the Vicat system for building in the United States.

“Cinder blocks operate on the premise of a vertical footing and a post beam around top of the house,” Glen Donoghoe of HempBLOCK USA told Hemp Build Mag. 

“The vertical post ties the building together to the beam, and hemp blocks do exactly the same thing.”

Installed blocks are covered with lime plaster or stucco.

Hempcrete has not yet made its way into U.S. building codes and is uncommon in regional or local builds, but building inspectors understand the steel cage and cement support system, Donoghoe said.

The BIOSYS system, licensed by HempBLOCK, uses precast interlocking hemp blocks that can also save labor and time. The outer walls of a house can be built by relatively unskilled labor within days, and about 70% faster than a concrete wall, Donoghoe said. In contrast, it takes about two months to construct outer walls with traditional stick framing, insulation, plastic wrap, siding and drywall.

Donoghoe runs the company from the mountains near Toulouse, France. Currently, he manages container shipments of BIOSYS blocks, about 600 per container, with binder or enough to build the walls of a 2,400 sq. foot home for around $30,000. Shipments from France take six to eight weeks, Donoghoe said. 

He acknowledges this delivery method is not carbon-neutral, but the system is working until a reliable U.S. supply chain can provide building quality hemp hurd in large quantities. 

 “If we can manufacture locally, reduce the carbon footprint and add value to local economies, people would be buying locally and we’d be employing people,” he said.  

“Everybody wins in this scenario.”

‘Lego’ system

Another load bearing hemp block system was developed by British Columbia-based JustBioFiber. 

“We’re the only pre-engineered structural building system based on hemp,” JustBioFiber CEO Denver-based Dave Ladouceur told Hemp Build Mag. 

“We take your drawings and floor plans and our software automatically converts them into block-engineered buildings.”

JustBioFiber made a splash with the Harmless Home, a magnificent hempcrete residence built in British Columbia for a private owner. https://cdn.embedly.com/widgets/media.html?src=https%3A%2F%2Fwww.youtube.com%2Fembed%2FH8efNdG7au4%3Ffeature%3Doembed&display_name=YouTube&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DH8efNdG7au4&image=https%3A%2F%2Fi.ytimg.com%2Fvi%2FH8efNdG7au4%2Fhqdefault.jpg&key=61d05c9d54e8455ea7a9677c366be814&type=text%2Fhtml&schema=youtube&wmode=opaque

But the company has its sights set on large developers building hotels and other large projects. JustBiofiber recently constructed a building on the campus of the University of Trent in Canada. 

The company also builds a foundation block out of recycled plastic which can save time compared to pouring cement foundations.  

“We are not the product to be found at Home Depot,” Ladouceur said. “Our focus is to become the premier sustainable building products company in the world. We are looking for large scale master developers who are going to make a commitment to JBF products in the market. Building one-off housines is not efficient for us,” he added. 

But the pandemic took its toll on the Calgary-based company, he said.

“We have back orders for millions of blocks we can’t fill,” he said.

The company is in talks to build factories in Texas, Missouri, Arizona and New Mexico, he added.

Adobe hemp blocks

Other U.S. engineers and architects have experimented with mixing hemp with other, more load-bearing materials, such as adobe clay, but commercial applications are not quite available in the market. 

Hemp blocks as insulation

Hemp blocks without the structural component can also replace expensive lumber when used as insulation. 

Pre-cured hempcrete bricks 8 x 16 x 6-inches installed with mortar by masonry professionals can be used along with a wood frame construction to provide “shear” horizontal support usually taken up by particle-board OSB.

Hemp blocks work well as insulation because of air pockets trapped in the fluffy hemp within the lime blocks. Unlike Portland cement, walls do not crack with freeze-thaw cycles because hemp and lime regulate moisture inside a building and wick it to the outside. Hemp insulated homes save on heating and cooling costs and have highly rated acoustic properties. 

Whether U.S. builders and consumers will embrace hemp blocks remains to be seen. But lumber prices may cause the U.S. construction industry to think outside the timber-framed box. 

“Changing construction habits is indeed a long term challenge,” IsoHemp’s De Bellefroid said. “Architects, contractors, project owners, we all need to adopt new ways of building.” 

But the hemp block’s thermal and acoustic insulation, water regulation, fire resistance as well as a negative carbon footprint makes it “a material that revolutionizes the building industry,” she added. 

Editor’s note: A JBS block video formerly seen on this story was incorrectly identified as featuring hemp blocks. The video featured another JBS product, a foam block.

Jean Lotus is editor and publisher of HempBuild Magazine. jeanlotus@hempbuildmag.com