Sealing before grouting is smart when using a dark grout color with light colored marble tile.
Carrara marble sealing before grouting.
Then i used a grouting sponge to wipe off any excess.
I have always sealed after but i have also done very little work with marble tiles esp dark colors esp on a floor.
You ll have to replace those to make it look even.
Hi guys i have a stone tiler fixing some carrara bianco in my bathroom.
I am using a grout from a store i never used before and they told me to seal the marble before grouting because the grout might stain the tile.
I just installed marble tile in an entryway dark green with dark grout.
Carrara marble needs sealed.
Because marble is a natural stone and will absorb color you need to seal them before you grout to prevent the grout from discoloring the tile.
The edges of the tile are much more absorbent and if the grout color is dark then the dark water from the grout will absorb into the edges of the tile and create a picture frame stain.
Now if your grout is a dark color then it can be advantageous to apply a sealer before grouting to keep the grout color from absorbing into the edges and discoloring the marble.
I prefer to seal mine before grouting.
Those couple of tiles must have been a bit more porous than the rest.
My guess is it wasn t sealed so a couple tiles soaked in some grout darkening them.