I just spent 2 weeks breaking up styrofoam that I got for my time to break them up for a super insulation I am making for my sand battery. Looking at this, I would be FAR FAR ahead if I would just pay for a load of sawdust for insulation, and go thicker with it.
The old ice houses were built with sawdust insulation, combining it with the mixture he suggests would greatly improve the longevity of the structure..
What impressed me so much about this video was his method of getting rid of thermal bridging. This man is one sharp cookie!!!!