Few plants have accompanied humanity as closely as cannabis. Used for millennia to make textiles, paper, and medicines, it has quietly shaped everyday life and built environments alike. Hemp, its non-psychoactive variety, is one of the earliest cultivated crops and a material of remarkable versatility: strong, breathable, and renewable. From ropes and sails to insulation and biocomposites, hemp’s fibers have been helping humans build for thousands of years.
In recent years, the spotlight on sustainable, eco-friendly, and low-carbon materials has intensified across the architecture industry. Amid this interest, a renaissance of hemp architecture is gradually gaining momentum on a global scale. Hemp-based materials have emerged as a favorable alternative to traditional industrialized materials, presenting a multitude of benefits that could revolutionize the construction industry. Despite its vast promise, several hurdles obstruct the widespread adoption of hemp, inhibiting its transformative potential in the construction industry.
The Royal Institute of British Architects (RIBA) has announced the winning projects for the 2022 RIBA London architecture awards. The list of 42 buildings includes projects ranging from a sustainable council housing development to a cookery school for children, showcasing the best architectural interventions in London over the past two years. The projects were selected by a regional jury, who visited all 66 shortlisted projects. RIBA London Award winners will now be considered for a highly-coveted RIBA National Award in recognition of their architectural excellence, which will be announced in June.
Every time we publish an article about Hempcrete, we get a lot of comments on social media - with a certain level of irony - about what would happen if the material caught fire. This is actually a legitimate question, as there is still a lot of confusion about the differences between marijuana and hemp, both of which come from the same plant species (Cannabis Sativa). But while marijuana has psychoactive effects due to tetrahydrocannabinol (THC), mainly present in the flowers of the plant, hemp-based building materials are produced from its stem, which contains small amounts of THC. To quickly answer the title question: no, the building won't be destroyed in the event of a fire. In fact, some tests have shown that these materials have excellent behavior against fire, dissipate flames, maintain structural integrity, and don't emit toxic smoke.
A lot of prejudice and contradictions surround the history of Cannabis sativa around the world. It is estimated that hemp was one of the first plants to be cultivated by mankind. Archaeologists have found remnants of hemp fabrics from ancient Mesopotamia (now Iran and Iraq) that date back to 8,000 BC [1]. There are similar records in China documenting the consumption of hemp seeds and oils, dating between 6 and 4 thousand BC. Upon its arrival in Europe, its main use was for the manufacture of ship ropes and fabrics: even the sails and ropes of Christopher Columbus' ships were made of this material. Likewise, the first books after Gutenberg's invention of the printing press [2] and many paintings by Rembrandt and Van Gogh were made of hemp.
The use of hemp for civil construction is not new either. Mortar made of hemp was discovered on the pillars of bridges built by the Merovingians in the 6th century, in what is now France. It is also well known that the Romans used hemp fiber to reinforce the mortar in their buildings. Nowadays, although there are legal barriers in many countries, the use of hemp as a construction material has had encouraging results, with research demonstrating its strong thermoacoustic and sustainable qualities. Hemp can be shaped into fibrous panels, coverings, sheets, and even bricks.
