Hemp shouldn’t be used at ground level, or it loses its resistance to mold and rot. Lime plaster coatings or magnesium oxide boards have to be applied to anything touching hempcrete, or the lime will calcify it and lose its ability to absorb and release water.
While that sounds like a lot of work, Ms. Beckerman pointed to the long-term payoff.
“In many climates, a 12-foot hempcrete wall will facilitate approximately 60-degrees indoor temperatures year-around without heating or cooling systems,” she said. “The overall environmental footprint is dramatically lower than traditional construction.”
There still aren’t international standards for building with hemp, or codes regulating how it should be used structurally or safely. ASTM International, a technical standards…