Noob to earthbags

New to all this here. I am wanting to build an earth building office/workshop. My original design was going to be a stick build but doing some searching i found this neat little idea of earth bags. The cost i figure for a stick build would be around 4000-4500 for a 16x28 shop/office. I am trying to keep the sqft around 400-500sqft but would really like to do this in an earth bag. I live in northern part of FL close to the AL line so i am not right on the water table but getting close so i can only dig down maybe 3-4ft. Secondly my yard seems to be a higher content of the red clay around here but i have yet to do a soil test. My questions are as follows;

1. For my area (North panhandle of FL) what is the best mix?
2. What kind of bags would suit my building better (solid weave bags or hyperadobe?)?
3. If hyperadobe should i also use barbed wire like the solid weave bags?
4. If i wanted to build say a round dome with a diameter of 28ft how high do i need to go? (Most sites seem to indicate the diameter is the same as the height)
5. Should i also use a buttress?
6. Should i use rebar and if so can someone show me some ideas of using rebar in this kind of a structure?

Lastly just to throw you all for a loop for the design I have been looking into, i am looking at completely covering the structure with earth like a little hobbit home for a living roof which brings up a question of

1. Should i adobe plaster the outside or just throw a pond liner over top?
2. What kind of flooring should I be using, concrete slap or tile, etc?


The purpose of this project is to make as close to a naturally cool structure as possible where a section of it will be used for my office for working at home, while the other larger portion for all my other activities such as wood working, storage and my general man cave.

Thanks guys in advance.

First things first. If you're serious about this buy the book Earthbag Building by Kaki Hunter and Donald Kiffmeyer.

Buying and reading the book will be much simpler than me trying to explain everything here.

How you will want to design your shop is up to you, but if you want to use on site soil, you will have to bury it a bit. But in consideration of your water table, you may be better off having road grade trucked in and building up.

For the size of building you wish to build, just remember that it will be very labour intensive and you may spend the better part of a summer or season building it unless you have very, and I mean VERY good friends. Or you could throw a workshop In my experience, workshops are great for getting free labour, but you should charge people to attend or they won't show up. When people put a monetary value on the things they learn they are more willing to do them.