Slab on grade floor repair
About 20 years ago two rooms were added onto this house, both have a slab on grade and the floor tiles are cracking, i had to repair a wall in one of the rooms, and it looks like the floor was the slab with a styrofoam sheet on top (2-3 inches thick), with 1/4in plywood, black adhesive (tar?) and kraft tiles on top (i have no idea what these tiles are called, they are 12×12 in, used in many schools and older buildings, are less then 1/4 in thick and are the same fibrous material all the way through (and i’m hoping not asbestos, they were installed about 10 years ago i am told).
What is a better way to replace this with a durable floor, i have no experience with slab on grade (and i’m a DIYer not a construction worker). I don’t have ceramic tiling skills, but i think Styrofoam and such thin wood are not good ideas.
Both rooms have floor flex and cracking, i am assuming the second was built the same way, though i have not torn it up to find out, they were done by the same contractor (the tiles were done a decade ago when other repairs were done, i don’t know what the tiles would have been before the current ones but i doubt that matters).