Phil L wrote:

Big snip

but I'll reiterate WRT the floor
scrabblers - they don't work

Is this one of those machines much like a rotating vertical cylidrical
object fitted with tungsten carbide cutters on the bottom?

If so, the builders had to use one of those when the concrete arrived
for the new school classroom.
They couldn't get any water into it and it was setting as they laid it.
They spent the next 2 days trying to get the floor smooth and level.

Dave