As Lumber Prices Skyrocket, Builders Give Hemp Blocks a Second Look

June 2, 2021 at 5:41 pm

The cost of wood has gone up by 500% in a year, pushing more builders to consider hemp building materials

Hemp and lime blocks built in Pennsylvania are used for building insulated walls. Credit: Coexist Build

In April 2020, lumber cost a little over $300 per thousand board feet. Today, the same amount costs just over $1700, according to lumber futures data from CME Group.

That’s a 500% increase in just over a year.

The leap in lumber costs has added a whopping $36,000 to the cost of the average new single family home, according to the National Association of Home Builders.

The sticker shock is leading some home builders to take a second look at hemp.

Pretty much all the wood used in a home build, framing lumber, OSB plywood, and other wood building materials, can be replaced by hemp blocks, says Hemp Build Magazine.

Like cinder blocks, but better, pre-fab hemp blocks can be fitted together like Legos around a steel frame to build strong, longer-lasting walls, faster and cheaper than wood-framed walls.

Made with hemp hurd and lime binder, “hempcrete” blocks are are much lighter and more insulating than concrete.

And unlike wood, they are fire-proof, mold-proof and pest-proof.

After hemp blocks are assembled, they are covered with lime plaster or stucco.

HempBLOCK USA uses precast interlocking hemp blocks, which can be stacked into walls by relatively unskilled labor within days, as opposed to the average two months it takes to build walls using traditional stick framing, insulation, plastic wrap, siding and drywall.

Credit: HempBLOCK USA

Hempcrete has not yet made its way into U.S. building codes, but “building inspectors understand the steel cage and cement support system,” says Glen Donoghoe of HempBLOCK USA.

Hemp has been used widely in European construction for 30 years, but the U.S. construction industry is notoriously resistant to change and innovation, Hemp Build Magazine notes.

The growing number of U.S. hemp builders are hoping unprecedented lumber prices will help hemp construction go mainstream.

Another benefit of hempcrete is it sequesters carbon. All the carbon in the hemp is locked into the blocks with the lime binder.

“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, of Belgium-based IsoHemp says.

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.

British Columbia-based JustBioFiber, which pre-engineers hemp-block buildings based on customer’s drawings and floor plans, says it has millions of back orders it can’t currently fill.

The company, which focuses on hotels and other large building projects like universities, is looking to build factories in Texas, Missouri, Arizona and New Mexico to keep up with demand.