Grouting travertine is among the most complicated grouting jobs, because of the nature of the tile. Travertine is full of naturally occurring craters and pockmarks on its surface, which is part of its unique look. When installing travertine in the home, you’ll usually fill those holes with grout, so they don’t collect dirt, using a contrasting color from the tile so the patterns of the holes are still visible. The problem is, the grouting process will stain the travertine unless it’s sealed first.

1
Install the travertine with mortar, properly spaced. Let it set for at least 24 hours.

2
Apply a layer of penetrating liquid tile sealant over the flat parts of the surface of the travertine, using a paint brush. Don’t brush it into the spaces between the tiles or in the holes and craters on the tile surface. Let the sealant dry for three or four hours.

3
Spread grout over the surface of the travertine with a grout float, starting in one corner and working your way out over the whole span. Run the long edge of the float along the surface, scraping the grout from the surface while forcing it into the holes and lines and flattening it out there.

4
Let the grout sit in the holes and lines for 10 minutes. Wipe down the surface with a damp, well-wrung sponge to take up the excess grout.

5
Let the grout set for at least three days. Brush a layer of tile sealant over the whole surface, including the grout. Let it dry for four hours. Apply a second layer.