wrote

Concrete , 4" thick , directly over the sand which i currently have as
a floor . He said there are stones mixed in with the concrete about

One of the things I've noticed in passing, is almost all driveways folks
talk about here are poured 6 inches. This could be a code issue combined
with how cold your area gets vs theirs, or a longevity one. Not really
sure.

Also, his workers for that price may not have insurance if they get hurt on
the job. That means they can sue you for hiring them if they get hurt (it
takes little to check this out and in fact if fully insured workers, he
likely pointed it out already).