We sell two different types of Travertine Tiles.
Brushed & Chiseled Travertine Tiles: Can be used on a covered patio or porch as well as indoors. The surface is not tumbled and therefore will not absorb water very quickly. For this reason, we do not recommend using them around a pool area.
Honed & Filled Travertine Tiles: Recommended indoor usage only. These tiles could technically be used in a covered porch area, however the border of the porch that is exposed to the elements could become slippery with standing water.
See Travertine Tiles here.