Installing slate tile on a floor is similar to the installation of ceramic tile. This means that the tile will require a solid surface or sub-floor for installation. The flooring can be prepared by using plywood underlays that have been secured, with screws, to the sub-floor before laying the tiles. You can install a slate tile floor by first determining the type and size of tile that you want to use on the floor.

Instructions as follows: 

Firstly, Measure the width and length of the room to tile with the tape measure. Determine the center point of the room and make a mark on the floor with a pencil.

Secondly, snap a chalk line over the center point of the room. This will give you a reference or starting point for the tiles.

Thirdly, set the tiles on the floor to see how they will look. This is called a dry run which will show you if any of the tiles need to be adjusted to fit correctly.

Fourthly, pick up all of the tiles from the floor and then mix the thinset mix in a bucket with water. Follow the instructions on the package to properly mix the thinset.

Fifthly, apply a small amount of thinset to the floor with a trowel. Put ridges in the thinset by using the grooved end of the trowel.

Sixthly, apply a small amount of thinset to the back of the slate tile with the trowel. This is called back buttering the tile.

Seventhly, set the first tile in place along the chalk line. Tap it into place with the rubber mallet. Back butter the second tile and set that in place next to the first tile.

Eighthly, insert a spacer in between the tiles to leave a space for the grout.

Ninthly, repeat steps 5, 6, 7 and 8 until you have finished laying the tile on the floor. Wait at lest 12 hours for the thinset to dry.

Tenthly, apply the grout to the tile joints using a grout float. Place a small amount of grout over the joint and use the grout float to pull it into the joint. Repeat this process until all of the joints have been grouted.