Hemp is actually one of societies oldest cultivated plants and has only in the past century gotten a bad name mostly due to political and financial interests wanting to dissuade its use. But recently it is becoming more popular again as a building material.
Check out these videos on the topic. They show how hemp is a very good alternative to many conventional building techniques.
Part 1
Part 2
They mix one bale of hemp with three bags of lime.
French hemp building
“Stronger than cement and 1/6 the weight.” The builder is held back only by legal restrictions on hemp production.
1st Permitted Hemp House in the US
About Hemp-Technologies.com. Lime is better than cement because it does not need to be heated like cement. Lime draws CO2 out of the atmosphere and gets harder and harder over time. The walls last for thousands of years. It doesn’t start out structural but over time it becomes structural. Hemp dries out a lot better than straw bale and thus is better in terms of mold.
Spraying Hempcrete
Hemp production and construction
Film done by Lime Technology, another hemp player. Shows blow on hemp, skim coats and lime wash paint process. Hemp by Tradical hemp producer.
Hempcrete reuse
Unlike cement, hempcrete can be recycled.
Hempcrete.ca
How to make a hemp house in three minutes!