What is Hempcrete? [Custom Home Build]
What is Hempcrete?
Hempcrete is a natural building material composed of hemp hurds, lime-based binder, and water. The material is considered a "hemp-lime bio-composite" in industrial terms.
The hemp hurds are processed from the hemp stalk which is then dried and shredded to a wood-chip consistency. The hurds are combined in a mixing drum with the lime-based binder and water until you've reached the desired consistency. Workers then use a small tote (approx 25L) to transfer the mixture to the wall forms.
The building is framed up using traditional stick-frame construction, the electrical and plumbing coordinated and installed within the walls before the Hempcrete is applied. OSB sheets then go up around the studs and spacers just as concrete form-work would be arranged. The labourers then pour the mixture into the voids, level, tamp, repeat.
Ok, that's great. But WHY Hempcrete?
The benefits of Hempcrete are truly astounding. Once you learn what you're about to learn you will wonder why this hasn't taken off like a... err... wildfire? (too soon)
Hempcrete is fireproof.
(Read that again)
Yes, that's right. In this hell-scape of a summer a lot of us experienced and now looking to the future wouldn't it be assuring to know that your house wasn't going to burn down? Wouldn't you sleep better at night knowing that the electrical system in your walls won't fail while you sleep and you experience a traumatic house fire? Or maybe you are a landlord and could rent your fireproof house to tenants that won't burn down your investment? I bet you'd like that. I bet your insurance company would also like that.
Hempcrete Buildings are Carbon Sequestering.
First, a growing field of hemp is a massive natural carbon-capturing machine. So is a forest. It's what plants do. But hemp goes from seed to harvest in 60-90 days compared to pine trees in the forest that take 25-30 years to mature before harvest. The right Canadian conditions could see 3 hemp harvests in one calendar year.
After the plants are cut down, processed, and applied as Hempcrete it continues to sequester carbon for the lifespan of the house which could be north of 100 years. Every new home built in our country, and frankly across the world, will be pulling carbon out of the air and burying it within the walls. The case is the same on the interior of the building, pulling unsavoury toxins into the centre of the mass as part of the curing process.
If there is ever a need to remove parts or all of the house in the case of damage or renovation the hempcrete mass can be crumbled and returned to your garden or re-used in a new application to save on material. So yes, it's biodegradable and re-usable. Can you picture crumbling fibreglass batt insulation into your garden after a reno? No, that would be ridiculous. So is using ineffective traditional materials in the face of a climate disaster.
Hempcrete Replaces all Building Envelope Materials.
Including paint! The hempcrete mass is applied between, in front of, and behind the timber studs and is finished on both the exterior and interior with a skim-coat that is trowelled on. You can choose the tint of the skim coat to customize your space, and the colour can be updated in the future if necessary by using natural, breathable paint.
Hempcrete replaces exterior cladding, sheeting, vapour barrier, insulation, drywall and paint. Magnesium Oxide Boards can be used in interior applications if the client desires a drywall-like finish.
Once you factor in everything Hempcrete replaces it is fair to say that it is comparable to traditional material and installation costs with Hempcrete in the Okanagan coming in at approximately $24/ft2 installed including material and labour. The savings on heating and cooling during occupancy are also profound and provincial energy rebates and credits are also an available benefit to the client. A home that uses either wind or solar energy collection could further credit the homeowner's bank account if they were tied into the grid, you won't use nearly as much energy in a Hempcrete house and could see decent savings on the power bill as a result.
Hempcrete is Mould & Pest Resistant.
The pH of the binder is so high that it creates an inhospitable environment for mould to survive, it is also built as a monolithic, solid mass so no unwanted animals or insects can compromise your health or your structure. It is also a breathable, vapour permeable material that naturally regulates the interior air to between 40-60% relative humidity making it excellent for those prone to asthma, allergies, or other respiratory afflictions.
Hempcrete Has a Very High R-Value.
Traditional concrete applications often have an R-value of about 0.08/inch of thickness compared to Hempcrete that clocks in at 2.4-4.8/inch depending on the thickness. A 12” hempcrete wall can achieve an R-value rating of 42 when installed properly, and if a customer wants even higher performance we could install a 14”, 16” or 18” exterior. As we continue to experience extreme weather events our health and safety depend on the performance of our envelope materials.
Hempcrete is also considered a "thermal mass" which means that when the heat from the sun is beating down on the exposed wall it is slowly passing heat from the outer surface through the middle and out the other side (which would be the interior of the house). By the time the sun goes down and the temperatures drop, the air cools the exterior of the building until it reaches the inside of the house thereby cooling the interior during the day. This system will dramatically reduce our need for fossil fuel-powered heating & cooling sources.
Hempcrete is A Natural Energy Solution.
This means it is covered by homeowners insurance and is considered a "Better Than Net-Zero" product. With our province positioned to be Net-Zero by 2050 you will see an incredible ROI by using Hempcrete.
Hempcrete is Made In Canada.
Hemp is being grown widely throughout the prairie regions of Manitoba, Saskatchewan, and Alberta; as supply-demand grows we believe more prairie farmers will leave behind their chemical-laden, carbon-producing, industrial agriculture mono-crops and opt for the profitable, clean, renewable, climate-change protecting fields of hemp.
Anyone Can Do It.
We recommend you hire the professionals so you get a superior installed product at the end, but our local installer Hemp-Works Canada is also a distributor of hurd and binder and is also available as a hired consultant to teach you, your family, or your volunteers how to build their own Hempcrete building!
So, have we convinced you yet? We hope so, our collective future depends on it!
If you'd like to review the detailed specs provided by Hemp-Works Canada please click here.
If you would like to ask Hemp-Works Canada some technical or investment questions please click here.
If you would like to book a design consultation with us please click here.