Just went and did a estimate on a slate job, roughly 60 square feet. It's black sigh very dark grout lines, they had a rug down with adhesive on the back and looks like they used some sort of cleaner to remove adhesive and it removed the black in some areas making it very dull and much lighter, what all would be required to turn is back to good condition.. I have included some pictures, I have done tile before just not to much slate and really don't want to pass the job up because it came from...
Slate job - need some guidance
Slate job - need some guidance