Hemp in our homes
— Éco Habitation
Hemp offers many advantages, with nearly endless applications—from woven fibers to edible seeds and cosmetics, to bioplastics, and even oils and plasters. And one of its most promising uses? As a building material. But because it closely resembles its cousin marijuana—a plant of the same family used for medical and, more recently, recreational purposes—hemp is often misunderstood and confused.
This confusion is also why hemp remains relatively unknown; for a long time, its cultivation was banned. Yet when used as fiber, hemp is extremely durable and on the path to (re)becoming a traditional and accessible material, notably in forms like insulation (batts), sprayed applications, mats, and even concrete.
Hemp: An organic raw material with a fascinating life cycle
A unique growth cycle
Hemp can go from seed to harvest-ready plant in under 120 days, making it one of the fastest renewable materials on Earth! Some trees can take more than 120 years to produce the same biomass hemp produces in just three months. This ultra-fast growth cycle provides a major advantage, especially with its rapid carbon sequestration potential: by harvest time, one ton of hemp will have sequestered, on average, 1.62 tons of CO₂. That carbon stays locked in throughout the life of the material!Embodied energy, CO₂ storage, and End-of-Life
Buildings have a large ecological footprint and contribute significantly to climate change. One way to reduce this impact is to swap out petrochemical-based materials—massive greenhouse gas (GHG) emitters—for recycled or bio-based materials like hemp. In fact, hemp doesn’t just reduce GHG emissions; it also captures them. A medium-sized home built to maximize hemp usage could store over 20 tons of carbon dioxide (CO₂)! As for the embodied energy of hemp insulation, it’s only 50 kWh/m³, compared to mineral wool at 150 kWh/m³ and fiberglass at 250 kWh/m³. Hempcrete can also help reduce construction waste—another major issue. Concrete accounts for more than half of the waste generated from building construction and demolition. While hempcrete can’t be used for structural elements, it can act as insulation and a substitute for materials like drywall and plaster, which together make up about 8% of construction waste.A healthy alternative raw material
Hemp materials are non-toxic and contain no harmful glues or resins. The binders are typically made from sugar—yes, just sugar! To meet industrial safety standards, fire-retardant treatments based on salt can be used on panels and insulation, which also helps prevent mold and pest infestations (insects and rodents). And since hemp cultivation requires no herbicides or pesticides, manufacturing these materials helps protect the environment (air, water, and soil) and indoor air quality by reducing exposure to VOCs. Hemp is a truly compelling alternative, far less harmful to the environment than many other raw materials.Hemp materials: Ideal for an eco-friendly, high-performance home
Naturally hygroscopic and durable soundproof insulation
Thanks to its lightness, strength, and durability, hemp is perfect for many uses in the home: insulation, finishes, molding, cabinetry, shelving, furniture, tables—even countertops if properly sealed. It’s also easy to work with, and its lightweight nature lowers manufacturing and transportation costs.
Its primary use in construction is for its insulating power: hemp is an excellent thermal insulator (R 3.7 for batts, R 2.1 for hempcrete). It also offers soundproofing, high resistance, and long durability. Hemp essentially “petrifies” over time and helps prevent water infiltration, drafts, mold (antifungal), bacteria (antiseptic), and even rodents and insects. Experts believe a hemp house could last several centuries—some optimists even say millennia!
Fire-resistant with excellent thermal mass
Hemp is a mass insulation material: it also performs well against fire. After four hours exposed to a 650°C flame, a hemp wall shows no signs of combustion, and the temperature on the opposite side of the wall will have risen by only 2°C.
Hemp also offers excellent thermal mass. In fact, a hemp wall responds almost intuitively to temperature and humidity changes. So no dehumidifier, air conditioner, or humidifier is necessary.
Insulation, exterior and interior finishes: hemp in all forms
Hemp batts and mat insulation
In Quebec, the most common hemp insulation products are batts (like fiberglass), hempcrete, and sprayed hemp. Hemp batts aren’t fundamentally different from other natural insulations and can be installed without professional help in most areas of the home (except the basement). Hemp insulation is more expensive than mineral wool, but cheaper than spray foam. For example, Nature Fibres’ 5.5” hemp wool panels cost $1.90/sq ft, and 3.5” panels cost $1.35/sq ft.Hempcrete bricks: Affordable but non-structural
Hempcrete or hemp block walls are built using formwork: long hemp stalks are compressed under high pressure to create highly insulating blocks. These are placed between wooden studs and reinforced with mortar. Sprayed hemp offers good insulation values; the blocks provide long-term durability, but it’s essentially the same material in a different form—comfort levels will be identical. The choice of method depends on the building’s structure. Hemp is not suitable for foundations—it’s not load-bearing. Lab-made hempcrete has a compressive strength of 3 MPa, while typical concrete blocks range between 5 and 20 MPa. A wooden frame is therefore necessary—traditional framing, timber framing, double studs, or solid wood. Ideally, use locally sourced FSC-certified wood. Note: Electrical and plumbing systems should be installed **before** hemp insulation, just like in conventional construction. Electrical wires should be BX (metal-sheathed) or placed in tubing. For exterior walls (10” thick), costs range between $20 and $30/sq ft, including finishes. This varies by location and whether the project is turnkey or involves only technical assistance.New: Hemp construction panels
Sunstrand, a company based in Louisville, Kentucky, started by cultivating and processing industrial hemp. Shortly after its 2014 founding, the company began developing finished products. After noticing the market’s slow adaptation, they aimed to help other businesses see the potential of hemp in construction. One of their innovations is the Hemp Coreboard, a lightweight board made entirely from the core of the hemp stalk—designed as a sustainable alternative to particleboard.Hemp plaster: Healthy and authentic
Hemp plaster can be applied to both interior and exterior walls. It’s waterproof, airtight, doesn’t crack, and hardens well with exposure to air and water. 100% natural, it adapts to wall movements and is fire-resistant. Hemp-lime plaster keeps walls breathable by allowing water vapor diffusion, regulating humidity. Bonus: the binder is also antiseptic, antifungal, and anti-static! Hemp or lime plasters are also ideal for restoring old buildings. These heritage structures often use materials like stone masonry, earth, adobe, or wood—natural materials that allow vapor to move through and evaporate. According to Samuel Pépin-Guay of Linéaire Éco-construction and a member of our Expert Circle, the safest approach is to choose breathable insulation. Gabriel Gauthier of ArtCan agrees: “A more permeable material that regulates humidity is best suited to improving energy efficiency in historic buildings, while also respecting their need to breathe.” Impermeable coatings, like cement-based concrete, trap moisture inside walls. The resulting condensation can speed up structural deterioration, which is definitely not desirable! Lime plaster, however, allows gas exchange and enables moisture to evaporate freely. It also adheres well to natural materials, making it suitable for brick, stone, formwork walls, and timber framing. That’s why it’s widely used in heritage restorations. Still, it’s best to call in a pro—applying it properly takes some skill.Local professionals
Generally, people interested in hemp construction are also self-builders. If that’s your case, we recommend taking a training course before diving in. Ideally, visit a building site to see how things are done in practice!
You can also hire qualified contractors to build your fully ecological dream home—or to assist you with your build. In Quebec, the sector is expanding fast. Local insulation, tech support, training, qualified builders… Let’s take a look at what local businesses are doing.