what soil is filled in?

I planned to make a little studio with straw bales but due to a fooder shortage here I just can't find straw bales unless transport them a far distance. So I thought I switch to tires but I only read a little about building with tires...are there some good websites with how to....

I would have 2 first questions on building with tires:

1. Can I fill in any type of soil?
2. How can I insulate a tire wall?

Thanks for helping....

Hi Sophie
I found some good videos on youtube, try this one: https://www.youtube.com/watch?v=cY-ZboQqCu4

I have similar questions regarding material and would like to know if anyone has used clay since that's what we have. Good luck with you project.

Tire walls are themselves insulation. I think you can use whatever soil is available. We have black clay. We have to keep it dry when packing and after under it is sealed from the weather, but it has worked just fine. if you can put down plastic and pile dirt along the outside of the tire walls, then this will insulate them even further.

Hi there,
In January I completed the Earthship academy in Argentina where we did a start to finish build of a two room 'simple survival' Earthship. I continued to work with the government here in South America where we completed a rammed earth tire retaining wall which was made with 3,000 tires, so I feel confident in sharing what I learned in these projects about tire walls.
The tire wall itself is not insulation. It is thermal mass, so it helps regulate temperature but you still need insulation (if you want it to be auto-sustainable).
When building the retaining wall, we used all sorts of earth. I (and most of the people I worked with) liked working with dirt that had more clay, rather than more sand. When pounding the dirt in, clay will stay in place, and sand has more of a tendency to fall back out of the side walls.
Hope this helps:)
I'm going to try to attach a picture of the completed tire retaining wall.