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Introducing Hemp Slap Hut - India's first Wattle and Daub Hut with a Workshop Model

This is July 2021, and I am sitting under the constantly pouring rains in the frigid valleys in the Lug Valley of Kullu city. We have processed the fiber and used water retting method for removing the hemp fiber from the hemp stalks. However, the remaining question is what should we be doing with the naked hemp stalks. Two days ago, locals were advising me to burn them down. However, I am looking at it as not only a waste of the material but also, as another cause of environmental degradation with the smoke and carbon emissions.

All the major problems concerning the construction industry came running to my mind. First, in terms of health, cement construction workers face lung-based issues due to constant cement dust. Moreover, people living in cement houses can face knee-joint pain and foot pain due to walking on cement floor and residues from the dry cement can have some level of toxic skin irritants. In terms of cost, cement construction is expensive and not many alternate solutions have been explored other than lime. Environmentally, cement construction involves increased CO2 emissions and wastage of water and at the same time, increasing levels of mining for concrete and lime leads to soil destabilisation and depletion of minerals. Also, due to increasing reliance on cement, existing natural resources are burnt or left unutilised. Transportation involving cement leads contributes to the indirect environmental pollution as well. Moreover, how can we forget about the lack of alternate cash crops and models of development for farmers? Building with hemp was on my mind, but I did not think that it will have to be done so soon.

There was not concrete plan until Collin; a Civil Engineer from the California State University of Sacramento comes along and discusses conducting a workshop by creating the first unique build with hemp in the state of Himachal Pradesh. We spend next seven days discussing all possibilities in terms of what can be done and there, we were sitting on the idea of India’s 1st wattle and daub hemp hut. Wattle and daub is an atavistic composite building construction method where wattle (a woven wooden strip lattice) is daubed with a sticky material (usually a combination of straw, animal dung, sand, clay, wet soil, etc.). This method is present in the world for last 6,000 years and is still used in many parts of the world. However, our innovation in this method was the use of hemp in this building which was never done in the world before in terms of a big scale project in our knowledge. Surely, hemp was not used in a wattle and daub method before in India. Since daub is a process of smearing, coating or SLAPPING a surface with a sticky substance which was hemp in this case; we decided to name the building as Hemp Slap Hut and since, we wanted to teach the world about it; it led to the creation of the Hemp Slap Workshop.

After deciding the workshop, the very next challenge was to convert the fiber-less naked hemp stalks into hemp hurds, and we started building a hemp beater to break the stalks into small pieces of hemp hurds. However, our carpenter could not make it properly, and we found that hemp beater method was very labour-intensive too. Therefore, we decided to process hemp stalks in a machine, and we were successful in that.

We had sufficient hemp hurds to build a 13*13*15 feet hut, and we started planning it on 1st August. Workshop model was simple where participants like architects, civil engineers, and other eco-friendly hut enthusiasts can come and learn how to build a hut with local sustainable material including hemp in 20 days. We also had Sankara, Manimaran and Chirayu as volunteers which eventually led to the creation of Hemp Slap Crew with five initial members with Collin leading them from the front. We quickly made the logo and started promoting the workshop and got adequate response and workshop commenced on 1st August 2021. It was challenging because we were doing it in the rainy season, but this is the best way to analyse the properties of our mixes. Shreyas, a participant in the workshop ended up joining the crew after finishing the workshop.

In the initial phase of the workshop while we were preparing the land, we also conveyed various other methods of building like hemp bricks with lime and mud while using rammed earth methods to demonstrate the actual working properties of the hemp mix to the participants. We also segregated the hemp hurds in three different sizes so that we can use them in the roughing and finishing phases. Our Hemp Slap Hut is basically made with 100% indigenous cannabis hemp hurds, cannabis hemp broken fibers, local clay, consistent cow dung, bamboo and eucalyptus poles. Shreyas was tasked with calculating the total build volume for preparing the BOQ and eventually, after 20 days, hut was ready, and we started analysing its USPs.

USPs of Hemp Slap Hut

• Atavistic Wattle and Daub Building Method
• Made with 100% indigenous cannabis hemp hurds, cannabis hemp broken fibers, local clay, consistent cow dung, bamboo, eucalyptus poles, bees wax, flax seed oil and turpentine
• Unique but Repeatable with other locally available material
• Free from cement, concrete, and lime
• Carbon negative
• High thermal insulation
• Breathable walls
• Competitive cost (INR 1350 cubic ft) and Less time-taking (30 days) excluding interiors
• Modifiable with flexible build methods

When we observed the build, the insulation property of the hemp slap hut was highlighted where it used to be cozy and warm inside even when it was too cold outside. Moreover, wattle and daub building method ensured that less material was used since bamboo was also used as the wattle in the entire building. After completing the build, we started looking for an incubator for the hut and participated in FLCTD (Facility for Low Carbon Technology Deployment) where Hemp Slap Crew emerged as one of the 23 national winners and currently, the crew is competing with other winners for a $50,000 testing, validation and commercialization grant under UNIDO (United Nations Industrial Development Organisation), Niti Aayong and AIC-Sangam since November 2021 as a six months acceleration program.

While getting incubated, AIC-Sangam mentors provided us methods to conduct the real time impact assessment of our build and we realized that for every cubic feet of hemp clay mix, we can sequester 0.5 kg of Carbon which means our 300 cubic feet hemp slap hut is already sequestering 150 kg of carbon from the environment. Therefore, if we make 50 of such huts, it can lead to the sequestration of 7.5 tons of carbon from the environment into the huts. Moreover, there are external factors which are in the form of transportation and manufacturing of unsustainable materials like bricks, cement and concrete and lead to the increase in the carbon emissions. These factors can be greatly reduced and overall, construction industry can be decarbonized.

After successfully completing 3 months and carrying out comprehensive discussions with AIC-Sangam, we are conducting a free online workshop for discussing the benefits of hemp and its further applications in the construction industry. All the interested candidates can register themselves for the workshop here. This free online workshop is a pre-requisite to Hemp Slap Workshop 2.0 which we are soon planning as our next physical workshop. Hemp Slap Workshops represent a unique initiative by Himalayan Hemp to utilize all the material coming out of the hemp stalk while finding their application in the form of hemp sanitary pads for fiber and hemp slap hut for hurds completing the overall supply chain with impacts in the health care and construction.