Recently, I wrote an article about building earthen floors for Green Building Elements. Earthen floors are commonplace in straw bale and cob buildings, but they can also be installed in more typical suburban homes.
Check out the full article here: Natural Building 101: How to build an earthen or adobe floor.
Always lay the floor last so many people do it first then end up damaging it whilst completing the other works.
I just built mine in san angelo tx Mixed one part caliche one part earth two coats on linseed oil three coats of polyurethane. Its beautiful, I do recommend it greatly