Q. What are some installation and maintenance tips for my slate floor?
A. Here are a few tips:

Determine a Starting Point

• First measure and mark the center point of the two opposite walls in the working area. The center line can be marked by snapping a chalk line stretched between these two points.
  
• Duplicate the procedure for the other two walls. Use a carpenter square to verify that the two lines have intersected at a 90 degree angle (make adjustments if necessary). For rooms of irregular shape, simply select the most dominant area and make your marks.
  
• Begin laying loose tile along the center lines allowing adequate spaces for grout. If a space of less than half a tile remains between the last tile and the wall, move the center line one half closer to the opposite wall. Duplicate this procedure along the other line. Now you plan where to begin the installation. Move the starting line adjacent to the wall from which you wish to start the installation.
  

Setting Your Tiles

• Ensure that the subfloor is structurally sound and free of dust, paint, oil, grease and any other substance that may prevent or reduce the adhesion of the mortar.
  
• Choose a slate that is calibrated or "gauged". Gauged slate has natural cleft on one side and "grooves" on the other. The pieces come boxed and are the same thickness. It's very similar to laying a ceramic floor. Un-calibrated slate (slate with natural cleft on both sides and the pieces can vary in thickness) is very difficult and time consuming to install, even for the most experienced installer.
  
• Carefully clean off the surface of each tile with water and a brush or a wet sponge to remove dust.
  
• Apply the mortar to the concrete subfloor with the flat side of the trowel and then comb the mortar with the notched side of the trowel leaving ridges.
  
• Work in small sections at one time.
  
• Prior to setting the tiles, apply mortar to the entire back of each tile.
  
• Firmly place the tile in position with a twisting motion so that 100% of the back of the tile has contact with the mortar on the floor.
  
• Do not disturb the tile work for 48 hours.
  

Sealing and Grouting

• Using clean water, thoroughly scrub and clean the area to remove any remaining loose material or dirt from the stone surface. Take care not to disturb the bond of the tile to the mortar. Use kneeling boards if necessary. Allow the cleaned tile to dry.
  
• Apply a generous coat of the sealant and let dry for 24 hours before grouting.
  
• Grout floor
  
• Apply second and final coat of sealant and let dry for 24 hours.