Written by Alexander Light
What is Hempcrete?
“Hempcrete is a bio-composite made of the inner woody core of the hemp plant mixed with a lime-based binder. The hemp core or “Shiv” has a high silica content which allows it to bind well with lime.
This property is unique to hemp among all natural fibers. The result is a lightweight cementitious insulating material weighing about a seventh or an eighth of the weight of concrete.
Fully cured hempcrete blocks float in a bucket of water. It is not used as a structural element, only as insulating infill between the frame members though it does tend to reduce racking. All loads are carried by internal framing. Wood stud framing is most common making it suitable for low-rise construction. Hempcrete buildings ten stories high have been built in Europe.” 
|Hempcrete house; ©Copyright Hemp Technologies USA;|
HEMPCRETE has no equal as a natural building product, sequestering carbon dioxide for the life of the building.
Created by simply combining water, hemp aggregate and a lime-based binder it produces a building product with excellent thermal insulating and acoustic properties. The insulation forms the entire wall with the load bearing timber frame fully encased. Hempcrete is not just an insulator – it buffers temperature and humidity, prevents damp and mould growth, making the building a comfortable healthy environment.
“IT IS A BIT DEARER, BUT A LOT BETTER!”
|Hempcrete ECO house concept;|
Hempcrete buildings last as long as a castle and save energy for ever. It is fire and termite resistant, lightweight and forms a hard wall surface yet is vapour permeable to help reduce humidity and prevent condensation – a truly natural product.
People that live in hempcrete houses do not need to run airconditioners or heaters all day to keep a comfortable home. Regular insulation requires constant energy input – hempcrete doesn’t. The way energy costs are rising, that’s a massive yearly cost saving through power conservation. At the same time, less energy use, less pollution AND carbon sequestration by hempcrete – your hempcrete project will be carbon negative. 
Like other plant products, the hemp crop absorbs CO2 gas as it grows, retaining the carbon and releasing the oxygen. 165 kg of carbon can be theoretically absorbed and locked up by 1 m3 of hempcrete wall over many decades. 
Drew Guarini investgated the subject and wrote for the Huffington Post: “Imagine you had a building material that was energy-efficient, non-toxic and resistant to mold, insects and fire. The material may even have a higher R-value, or thermal resistance, than concrete (a claim that is still being investigated).
The only problem? The base of the Hempcrete creation is hemp, which comes from the cannabis sativa plant — the same one that produces marijuana, which is a federally banned substance. Because of this, industrial hemp production is illegal in the United States.
Still, the Hempcrete mixture of hemp, lime and water is being used to some extent for construction jobs across America. One of the companies working with Hempcrete is ‘Hemp Technologies’, a construction company based in North Carolina that is adamant about the advantages of building using Hempcrete. They’ve built homes out of hemp in Hawaii, Texas, Idaho and North Carolina, where they are currently working on a project known as ‘NauHaus’.” 
|Hempcrete house under construction; ©Copyright American Lime Technology;|
The Benefits of Hempcrete, according to Hemp Technologies
– Thermal Mass Insulation
– Negative Carbon
– Low Density
– Clean Air
– High Thermal Resistance
– High Thermal Inertia
– Vapor Permeable (breathable)
– Design Flexibility (adjustable thickness)
– Fire and Pest Resistant (NO Termites)
– Significantly Reduce Co2 Emissions
– Inherently Airtight
– No Waste
– No Mould
– No Termites
– No Dry Rot
– Natural Substrates for Plasters and Renders
– Low Air Infiltration
– ZERO LAND FILL
|Hempcrete used for restoration; ©Copyright Sporn Construction UK;|
As one of the strongest fibers on the planet, hemp has been cultivated for more than 10,000 years. The long fibers of hemp mean items made of hemp for construction will be stronger and lighter than wood products. Not only does it hold nails better, particle board made of hemp can be twice as strong as wood. Moreover, just 1 acre of hemp produces cellulose fiber pulp equal to 4 acres of trees, so hemp could easily and efficiently replace most items made of wood. 
Originally posted @ Humans Are Free