I just finished the marble Floor for the Entrance Hall.
The floor was easy to make, but rather time consuming.
As with the firplace mantels, I strated by painting the illustration board a base color, let it dry 30 minutes, then took a wet sea sponge, squeezed out most of the water, dipped it lightly in the second paint color, then sponged it on making sure I turned the sponge to keep the pattern random.
The next day was cutting day. I cut the black marble into 1 " by 1/4" tiles, and the White marble into 1" x 1" and 1/4" x 1/4" tiles using a metal ruler and a sharp utility knife.
The next step was to cut a subfloor in illustration board to the dimensions of the room. because the tiles are not perfectly square, it was important to have guide lines on the subfloor to make sure the pattern was as exact as possible. I took out some graph paper with 1/4" x 1/4" squares and glued it onto the subfloor. Next, starting with the very center of the room, I glued the tiles in place with a regular glue stick.
The next day it was time to grout the floor. I like to use regular drywall spackle, the stuff that is used to fill small holes in the wall. With my finger, I went over the spaces with the spackle and tried to get into all the cracks. Then, I took a damp sponge and went over in circular motions to take off any excess spackle, and go over with a dry cloth. You have to make sure you don't apply too much pressure because you will push the spackle out of the cracks. The final step was to go over it with a steel whool, whipe it down with a damp cloth, and check the fit.
All in all, from start to finish, this floor section took about 16 hours of work. Thank God it's finished.