Hemp bast or long fiber and hurds or inner short fiber can be processed and used with existing technology in construction, and will solve the problem of adding strength and insulation to building materials. Hemp is a premium high strength fiber, similar to flax in many ways, a miniature forest grown in one season. The hemp stalk straight off the field can be incorporated into building materials because it has strength and engineering properties as does any cellulose stalk, but hemp has greater size and strength than many plants for its weight, growing period, and for our region. In the case of cellulose fiber having sufficient strength, bamboo has successfully been used as reinforcing rod in concrete instead of steel. Hemp fiber added to concrete increases tensile and compressive strengths, reduces shrinkage and cracking. Hemp processed with a hammer mill can be added to minerals in the class of Earth Cellulose building materials which is most easy to process. Earth cellulose material is suitable for use on farms and for urban projects. The material when incorporated in the proper design can be handled much like concrete at one third to one half the density of concrete. Batch plant trucks available now can drive to the site and mix the material for placement in form works, also available on a truck. Our production methods make use of straight and curved shapes to distribute stresses throughout the entire form of the building, which results in optimum strength.
Beyond harvesting hemp and high cellulose plants, products can be made on the farm with minimal processing and significant value added.
1. Whole hemp stalk mats or lattice matrix serve as a skeleton for building panels. Harvesting method: Heading, cutting, Stooking. The mats could be made near or right in the field and stacked for transport.
2. Bundled hemp stalks can be left in the field or retained for later processing.
3. Bundled hemp stalks can be used directly for structural use.
4. Semi decorticated hemp and hemp hurds can be formulated into building materials.
5. Hammer milled fiber crops can be mixed into concrete or as a concrete substitute with clay and gypsum and for processing into wall and roof panels made on the farm or on the construction site.
6. Mats of decorticated bast fiber as used in 1. above.
7. Cellulose fiber insulating plaster mix can be made in a similar way to the French Isochanvre.
8. Fresh, raw crushings of high cellulose plants in semi liquid form for making HempStoneô, and for including in formulations which make use of the lignin and other binding properties inherent in the high cellulose plant.
Decortication separates the long bast fibers from the shorter hurd fibers. Bast fibers are used in textile production and in oriented hemp board panels, in making interior panels for automobiles, rope, paper, etc. Hurd fiber can be used in insulation for construction, as animal bedding, to make paper, door core, plywood.
To make textiles several sequential processes are involved traditionally, but may be combined in one mechanical process with the proper equipment. Traditionally hemp was retted, or wet treated with microbes to loosen the lignin binding the fibers, then it was scutched to separate the dry fiber from the rest of the stalk, then hackled to comb the fiber, which aligns and separates bundles of cellulose into strands, then drawn five passes to make a continuous strand, called a sliver. The sliver is then roved to twist it slightly before being spun, woven and dyed. One machine developed by George W. Schlichten, US patent #1,308,376 (1 July 1919) produces a soft sliver from dry unretted stalks.
In contrast to this high value added processing which is very important to producing textiles, the use of hemp in building materials can use lower quality fiber such as that left from hemp seed grain production, and the amount of processing to reach the final product takes only a few stages. Farm processed cellulose would run through a hammer mill or through fluted rollers, much like gears, to decorticate the hemp, which separates the hurd from the long bast fibers. The hurds form an important insulation in construction materials.