My son Luke and I went to visit Brian, the owner of a hempcrete home I helped with 3 years ago. This is a huge 375m2 home with a giant 3 storey tower built by our friends at UK Hempcrete. The 420mm hempcrete is just about to get its two coat lime render now (hence the scaffolding in the pictures)... 3 years after being wet cast on site (cast like other concretes).
I have to say even I was amazed by how well the material has stood up to the weather: this is located on a hilltop beside Loch Tay, exposed to the fiercest Scottish weather. It looks like it was cast yesterday. Wet cast hempcrete is the best building material I've found - but our biocomposite IndiBlocs have the advantage of not having to wait to dry and only needing local masons.