This is a guest post by Vishal Vivek, co-founder of another hemp based company called "Hemp Foundation". I found his post here to be very interesting as I love hearing about uses for hemp in construction. I have long been interested in using Hempcrete and other materials in my own home and it's good to see that advancements are still being made in the field, along with discoveries of historical sites that used hemp which you'll read about below.
President and Creative Director of Datsusara
The construction industry is recognized to be one of the major sources of environmental pollution. Air pollution, dust generation, noise pollution, and vegetation removal are known to be the four major adverse environmental impacts caused by construction.
From roads and dams to office spaces and residential buildings - the list of construction needs is an ever-expanding one in an era when rapid urbanization is a feature across much of the globe. The environmental costs are heavy and constitute one of the key concerns today.
Stricter norms for the construction industry is one approach to reducing the impact. It is a welcome approach, but is it enough? Many believe that it isn’t, and with good reason. However, a not so well known and much-maligned plant has the capacity to transform the construction industry.
Hemp is what we are talking about here, which also goes under the name of industrial hemp.
It is an aromatic annual herb believed to have its origins in Central Asia. Planted for its edible seeds and its bast fiber, hemp has a cane-like slender stem that is hollow except at the base and the tip. The cultivation patterns for plants meant for seed use and plants meant for fiber use are different.
Cultivated densely together, hemp meant for fiber use grows tall and slender with virtually no branches. Those meant for seed use are grown much less densely so that they are shorter and have more branches. With palmate-shaped compound leaves, the hemp has two kinds of flowers.
The female plant grows flowers that produce the seeds while the male plants grow flowers that produce the pollen. Both kinds of flowers are greenish-yellow in color, with marginal differences in their appearance. Those with the seeds grow in spikelike clusters while those with the pollen form clusters of multiple branches.
Believed to be one of the earliest plants cultivated by human beings, hemp has a long history of human association for its multi-faceted uses. Plants grown for the use of their bast fiber are usually two to three meters tall, which translates roughly to six to ten feet. However, they can grow up to a height of five meters or 15 feet.
Hemp stalks, like the plant itself, is versatile and lends itself to many uses. One such use is as a building material.
Hempcrete for Construction
There are two main parts to the stalks: the fiber and the hurd. The hurd or shive is the woody inner core that remains after the fibers have been separated. Hempcrete is made by mixing the hemp hurds with binders like clay or lime, and water. In recent times, other binders like cement, gypsum, metakaolin, pozzolan, and sand are also being used.
Hempcrete in Ancient Constructions
Hempcrete is not a modern discovery, by the way. There are reports about the use of hempcrete in the underpart of a bridge in France constructed in the sixth century CE. An investigative study has proven that the Ellora caves of India, also constructed in the sixth century CE, used hempcrete.
These Buddhist caves declared a world heritage site by UNESCO, have survived the elements for more than 1500 years because of the use of hemp in the clay plastering. Scientists involved in the study report that raw, unprocessed hemp was used with clay and/or lime binder in the Ellora caves.
The pattern of use indicates that the ancient Buddhist monks were well aware of the exceptional qualities of hempcrete. The Ellora caves stand testimony to how hempcrete can increase the durability of buildings. They also indicate how ancient wisdom used natural resources for human comfort without destroying the environment.
Hempcrete for Sustainability
So, what makes the use of hempcrete enhance the durability of buildings? Well, like the plant it comes from, hempcrete is pest resistant. So, no mold or termite attacks, and that without the use of any pesticides.
Hempcrete has the added advantage of being fire-resistant. But its durability comes mainly from its ability to absorb carbon dioxide and harden. Hempcrete keeps on absorbing the carbon dioxide emitted by the occupants’ activities and becomes harder. Over time, it almost turns to stone.
Apart from making the building stronger, a hempcrete home is also a zero-carbon home, therefore. Instead of adding to the greenhouse gas menace, it helps the environment by absorbing and storing carbon dioxide.
Hempcrete for Insulation
Hemp hurds can trap air both inside their microscopic pores and in the spaces between the particles of the hurds. This characteristic gives hempcrete exceptional insulating capacity. It can also store heat inside the fabric of the material itself, once the lime binder sets.
Modern synthetic insulation depends on airtightness for heat preservation as they trap the heat in the air trapped inside the material. But hempcrete stores the heat in the material itself to release it slowly as the building gets cold. This heat does not disappear even if you leave some windows open for ventilation.
A second advantage of using hempcrete for insulation is that it releases the heat slowly. That allows a constant temperature to be maintained inside the walls without needing additional heating or cooling. Hempcrete walls are nature’s substitute for airconditioning. They keep homes cool in summer and warm in winter.
Hempcrete insulation saves on your fuel and/or power costs, therefore. The natural insulation of hempcrete also contributes to a greener environment by reducing our dependence on fossil fuels or electricity for cooling or heating.
Do remember in this context that electricity generation in itself burns a lot of fossil fuels. The carbon footprint of the process is huge. Reduced dependence on electricity would lead to lesser generation needs. That would contribute to decreased greenhouse gas emissions.
Hempcrete for Health and Peace
Greg Flavall, a celebrated hempcrete home builder, claims that people living in hempcrete homes demonstrate an improvement in their health status. He says this is because the natural air-conditioning eliminates the adverse effects of artificial heating and cooling using electricity or fossil fuels.
Admittedly, there needs to be research-generated evidence in support of Flavall’s claims. But his claim is not entirely illogical. Think of a concrete house in winter at a place with a subzero temperature. All doors and windows will be closed, and there will be a heating system for sure.
If the system depends on any kind of fossil fuel, there will be a lot of carbon dioxide emissions. Even if it is electrically operated, the cooking activities will emit carbon dioxide in that airtight home. So will the exhalation of all the occupants.
That is why houses with all doors and windows closed can become somewhat stuffy and that is certainly not a healthy living condition. Hempcrete walls, however, will absorb the carbon dioxide, saving the residents from breathing it back in. That does make hempcrete homes healthier.
When it comes to the peace issue, there is no scope to raise any doubts about the superior capacity of hempcrete. This material absorbs 90% of airborne sounds without any additional soundproofing.
Switching from concrete to hempcrete homes is a move towards a greener planet for all the reasons mentioned so far. However, a hempcrete home contributes to the environment even when it gets redesigned or is destroyed.
Concrete debris is a nuisance as a waste material. It mostly gets dumped in landfills and creates a number of environmental and health hazards. Hempcrete is entirely biodegradable.
Vishal Vivek, Co-founded Hemp foundation to increase awareness about the most misunderstood plant on the planet. He believes that we can fight climate change, water crisis and plastic pollution with Hemp. Hemp Foundation is the largest bulk hempseed supplier. Times Group recognized him as a legendary entrepreneur and published his biography in "I Did IT- Vol 2" at the age of just 30!
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