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‘Hemplime products are a superfood for the building industry’

BOOKMARK ARTICLE

Alison Mears and Jonsara Ruth, cofounders of the Healthy Materials Lab (HML) at Parsons School of Design believe we need materials that are good for the environment and for our health. Hemplime – a plant- and mineral-based alternative to typical construction and insulation materials, increasingly utilized by designers and architects – is one of them.

When it comes to addressing climate change, carbon emissions seem to be on top of the agenda. Why should we worry about the increase in toxicity in our materials and interiors to the same degree?

ALISON MEARS: Since the mid-20th century, building materials manufacturers have increasingly relied upon substances made from petrochemicals. These synthetic ingredients are mostly unregulated for their impact on human health and on the environment. Throughout the lifecycle of a material – from its raw material extraction through production, transportation, use, disposal or reuse – it impacts people's health, water systems, soil systems and biodiversity, or all living things. If we look at the impact of synthetic chemicals, the results are shocking and dramatic. Many of the human diseases that are so common today are a result of peoples’ exposure to these materials. And many of the polluted landscapes that cause our food and water systems to be hazardous are from the same materials and products. Yet regulations are slow to catch on, and builders, architects, designers and consumers continue to unknowingly populate our homes and living spaces with these materials. 

Photos: Felix Koch and Isabelle Young

Block House by Material Cultures and Studio Abroad is a Somerset residence that utilizes a natural material palette of locally sourced timber, hempcrete blocks and wood-fibre insulation.

According to your own account, no material you found is 100 per cent ‘good’ in all categories but there are superstars, one of them being hemplime. What makes it superior?

JONSARA RUTH: The industrial hemp and lime system, what we call hemplime – also known as hempcrete – is a viable alternative to typical industrial installation and insulation systems made from petrochemicals. It is a biocomposite made of hemp hurds, lime binder and water. The Hemp plant absorbs carbon as it grows and regenerates the soil. Its unique processing will create new healthier jobs in agriculture, manufacturing and in the masonry and construction trades. Combined with a lime binder, it can be made into a precast material which then can be installed quickly on site. It doesn't require flame retardants and other chemicals in the making. It creates energy-efficient buildings that are also breathable, meaning it moderates climate or humidity inside, and continues to absorb carbon throughout the life. At some point, in 120 years, when the building comes down, it nourishes the soil again. Hemplime products are a beautiful superfood for the building industry.

How does hemplime compare to building materials like cement or polystyrol in terms of costs, procurement and implementation?

AM: Typically, we assume ‘cost’ to mean the retail price of a product when the contractor buys it. But we ask: What is the true cost of the product from its inception – mining, refining, growing, manufacturing – to its point of sale? Does the cost of a product incorporate the carbon footprint of its production? And do we consider the lifecycle of the product and privilege transparent and circular systems of production?

Photos: Lori Daytner and Healthy Materials Lab

The Healthy Materials Lab pilot project PA Hemp Home in New Castle, Pennsylvania was a collaboration with DON Enterprise to explore renovation methods for healthy, affordable and visitable housing.

JR: Does the cost of a product include the health costs to communities living near production sites or disposal sites? Or what about the health cost to factory workers exposed to ingredients of a building product? Insurance costs to cover climate disasters caused by cumulative greenhouse gas emissions and health crises provoked by toxicity are increasing beyond affordability. The true cost of a product is much more complicated than an MSRP (manufacturer's suggested retail price). When compared to a rigid foam insulation (such as EPS, XPS, and polyisocyanurate) including the cost of materials, installation, thermal performance, embodied carbon and longevity we find hemplime to be a superior insulation material. 

What advice would you give to architects and interior designers who want to incorporate hemplime in their practice?

AM: Europe is a few years ahead of the US in terms of hemplime projects. It provides examples of excellent built precedents, prefabricated products and construction and detailing knowledge. By seeking out and referring to precedents, architects and designers can inform their own design process but also persuade clients of the climate and health advantages of incorporating hemplime. Besides, there are a range of government incentives for architects and designers to incorporate bio based, carbon sequestering products into projects to meet new climate targets, the RE2020 in France being one of them.   

JR: While it is an exciting choice, it's important to consult experienced builders and installers of hemplime. We have released a publication and other free resources that can help determine the appropriate installation method in line with project-specific factors including budget, available labor, and timelines. One of the constraints is climate and humidity, since hemplime requires ample dry time. In comparison, precast hemplime products, which dry in a factory setting, are most efficient because they can be immediately installed on site. 

Photos: Elodie Dupuis, Bertrand Fompeyrine

Architecture and landscaping firm Lemoal Lemoal erected hempcrete walls for the Pierre Chevet sports hall in Croissy-Beaubourg, France.

Further to its benefits for our health and that of the planet, what kind of aesthetic value can hemplime bring to a design project? 

AM: Design aesthetics can incorporate multiple attributes. As designers we hope that all of us think not just about the colour of a product for example in isolation but also consider where that colour might come from. If our paint is a white acrylic paint, the ingredient composition of that paint might include titanium dioxide for colour, and a plastic Vinyl Acetate Polymer as a binder. Both of these chemicals are known carcinogens. While we think of white rooms as clean and bright, we don't want to enclose our rooms with plastics – nor with toxic chemicals! As designers we help to chart healthy pathways for ourselves and our clients.

JR: A product such as hemplime does not only have benign ingredients but other, ofteninvisible, sensorial benefits. Hemplime achieves satisfying acoustic properties, and it also has an ability to regulate the humidity and climate in an interior space. These qualities exist because hemplime is inherently a porous, permeable material. When the surfaces are sealed with similar porous materials such as lime plaster, limewash or mineral based paints, the acoustic and breathable qualities are maintained. 

Photos: Emily Aquilina

Cover and above: Hempcrete is a key element in the Usquare.brussels development, which saw Brussels’ Ixelles/Elsene gendarmerie barracks turned into an open, mixed and multifunctional district. The practices responsible are BC Architects & Studies, Evr-architects, Callebaut Architects and VK Engineering.

What is the one most impeding factor for material health in the interior industry, which you would like to have removed first?

AM: Unlike the European context, the US has very few guidelines and regulations to guide the ingredient content of interior materials and building products. We are often confronted with products that contain a host of problematic content. With more guidelines and incentives to use better products we could make substantial gains to improve material health in interiors. And it would make it much easier if the materials industry was regulated to control the use of harmful chemicals. Then we could just concentrate on designing beautiful, healthy spaces for everyone.

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