The old floor is firmly attached to the underlying concrete, and is in pretty good condition except for surface dirt which I am pretty sure can be easily removed with a stiff scrubbing brush. My problem is that the tiles have shrunk over the 40 years and now there are gaps around each tile. The max gap is under 1/32”. I would like to figure out how to fill in the cracks/space between the tiles, bringing the filler up to the level of the top of the tiles so that the “cracks” don't fill up with the usual workshop floor dirt. Time to do the work is not a big issue, as I am sort of retired.
All suggestions will be considered.