from wikipedia (if you can trust)

Hempcrete's low density material and resistance to cracking under movement make it suitable for use in earthquake-prone areas.[12] Hempcrete walls must be used together with a frame of another material that supports the vertical load in building construction, as hempcrete's density is 15% that of traditional concrete.[13] Studies in the UK indicate that the performance gain between 230 mm (9 in) and 300 mm (12 in) walls is insignificant.[clarification needed] Hempcrete walls are fireproof, transmit humidity, resist mould, and have excellent acoustic performance.[14]