Do you seal limestone tiles before you grout or after?
You can seal limestone tile before and after grouting them.
Sealing them before will assure, that no grout absorbs into them during the grouting process.
However, be sure to clean your grout from the limestone tiles in a timely manner, because if the grout dries on the limestone tile, a haze can form on the tile.
After the grout has cured, usually 48 hours after grouting, you can seal both the tile and the grout.
Sealing before helps with preventing grout from absorbing and sealing after will protect both the limestone and grout from staining.
Remember, limestone and grout are very porous and sealing them won't make them waterproof. The limestone tile and grout need to be cleaned a sealed periodically to maintain them.
I hope this helps with the installation!