Re: slate in place now Christo,
You probably only need to seal it once, but that depends on abrasion and the appearance you're after. If there's lots of abrasion, as on an oven landing, perhaps once every year or two. If you prefer a shiny finish, as opposed to matte, once a year.
Jim
__________________ "Made are tools, and born are hands"--William Blake, 1757-1827 |