homemade wood fiber insulation.

In planning the construction of a monolithic (home sawn poplar and larch maybe CLT or DLT) timber house, I need to figure out how to insulate it cheaply. I really like the wood fiber exterior insulation, but it’s very expensive and it needs to be shipped from Europe. I’ve done some experiments with binding sawdust or shavings and starch together to make a board and I can say it’s more rigid than XPS foam which is impressive, but when it gets the slightest bit wet it’s done for. Has anyone ever done this? Does anyone know what kind of insulative values I could achieve with this as well as if I should add some borate for preservation and fire? Would adding straw and shavings make it stronger? Would adding biochar or cellulose make it more insulative? I’m thinking this is similar to chip slip insulation, but without the thermal conductivity and weight of the clay. Any other ideas on making this would help too.

Try coating it with linseed oil. Should strengthen and act as water proofing.

Similar problem here… remote location and importing stuff is neither easy nor cheap.
I had fairly good results with fireing a clay/sawdust mixture and turning it into a very porous brick. However it would require a large kiln to get the amounts needed for insulation.

If you could make enough clay/sawdust bricks for your needs, you could fire them as has been done in the past by making a big stack of bricks with flue channels throughout, firing the mass, then taking the stack apart, setting aside the good bricks, and putting the unfired ones from the outside of the stack in the middle for the next firing. Using good fired bricks for the outer layers in following firings would let you fire all the bricks you make.