Everything You Need to Know About Hemp Homes

Hemp homes are gaining popularity across the world in response to today’s environmental challenges and the necessity of finding sustainable alternatives to traditional building materials.

But is this a feasible option in Québec? 

Its Composition

First, it’s important to understand that hemp homes are mainly constructed using hempcrete, a composite material made of lime, water and hemp chaff (the woody stem of the hemp plant).

This mixture is then formed into walls, insulation, and sometimes floors. Unlike traditional concrete, hempcrete has no load-bearing capacity and so is commonly paired with a timber frame.

Its Appearance

Hempcrete walls are light brownish-grey and textured, somewhat similar to lime. Nonetheless, some companies offer a range of finishes and colours, from the material’s natural hue to a traditional plaster look to a log cabin style.

Hempcrete is vapour-permeable, which means it naturally regulates humidity levels by absorbing and releasing water vapour. Therefore, if the owners decide to cover the hempcrete walls with another finishing material for a more contemporary style, they must choose a breathable material, like wood.

And so, in certain instances, a hemp home may be almost entirely indistinguishable from a conventional house.

The Basic Building Process

Building a hemp home typically involves the following steps.

1. Choosing a Framework : A hemp house is generally erected on a wooden frame, which serves as its load-bearing structure.
2. Mixing and Applying the Hempcrete : The mixture of lime, water and hemp is applied in successive layers onto to the structural frame. It can be sprayed or poured into a formwork.
3. Drying : The application completed, the hempcrete must dry for several weeks before being covered with a finishing coat.
4. Applying a Finishing Coat : Lime plaster is usually applied to protect the hemp walls and to make them beautiful.

All the standard interior finishing material can be used inside the home when it comes to the decor: ceramic tiles, hardwood or vinyl flooring, etc. That said, people who decide to build a hemp house often aim to make it as green as possible and so opt for recycled or environmentally friendly materials.

The Advantages of a Hemp Home

1. A Thermal Insulation and Soundproofing Champion : Hempcrete is renowned for its exceptional insulating properties. It retains heat in winter and keeps the house cool in summer, reducing energy consumption for heating and air conditioning. Moreover, it absorbs sounds, providing excellent acoustic comfort.
2. A Renewable and Environmentally Friendly Material : Hemp grows quickly and requires very little water, fertilizer, or pesticides. Its cultivation contributes to the capture and storage of CO2, making this material even more eco-friendly.
3. Natural Moisture Regulation : Thanks to its hygroscopic properties, hempcrete naturally regulates moisture levels in a home, thus preventing mould and keeping the air healthy.
4. A Strong and Durable Building : Hempcrete doesn’t compress over time. It’s equally insect- and rodent-proof as well as fire-resistant, making it a safe material for residential construction.
5. Maximum Indoor Comfort : In addition to being insulating and breathable, hempcrete is a bio-composite that doesn’t release any volatile organic compounds (VOC) (contrary to synthetic materials), thus ensuring optimal indoor air quality.

The Challenges and Drawbacks of a Hemp Home

Despite its numerous benefits, a hemp home does come with some downsides.

• Higher upfront costs: On the one hand, materials and qualified professionals may cost more than for a conventional build. On the other hand, the long-term energy savings often make up for the initial investment.
• Longer drying time: Hempcrete needs several weeks to dry completely, which may extend construction deadlines.
• Weak structural integrity: Hempcrete can’t bear heavy loads and therefore requires a structural frame, usually timber.  
• Limited regulatory approval: Many jurisdictions’ building codes don’t currently include hempcrete, Québec among them, making obtaining permits more challenging.
• Harder to achieve seamless repairs: Holes in hempcrete walls are easily fixed; however, ensuring the repair matches the existing wall colour can prove quite difficult.
• Vulnerable to winter conditions: In northern climates, protecting hempcrete walls with wood siding is recommended to prevent damage from snow and ice. 

Where Are They Most Common?

France is one of the pioneers of hemp construction. The material has been employed in many sustainable building projects since the 1990s. The United Kingdom and Germany are both also beginning to adopt this technology. The use of hemp in construction is spreading in the United States, particularly in California and Colorado.

In Québec, hemp homes are still rare, but interest in this type of construction is increasing. A few residential and commercial projects have been undertaken, mostly by environmentally conscious architects and developers.

With a growing awareness of ecological issues, hemp could well emerge as one of the top building materials of tomorrow.