In the case of travertine the back of the tile is smooth so a larger notched trowel wouldn t necessarily be required.
Thinset thickness for large wall tile.
Jun 11 2011 the thinset thickness is determined by the size of the trowel used and the size of the trowel is determined by how the back of the tile is constructed and the size of the tile.
A 3 8 x 3 8 trowel will leave a 3 16 bed of thinset beneath the tile.
Using a u notched trowel and embedding the tile into the thinset leaves you with a bed of thinset beneath the tile a little over 1 3 the size of the trowel teeth.
Many thinsets max out at 1 4 in a single layer.
Spread the mixture using a notched trowel whose notch size.
A chemical reaction takes place within 30 minutes of mixing that starts the bonding process between the tile and the underlayment or wall.