Appearance

• Slate tiles are made from a metamorphic stone. Layers of mud that were compacted and transformed into stone through heat and pressure produced a stone that is naturally cleft into many layers. Slate, therefore, can be naturally split into rough tile sizes or cut and ground down to uniform sizes,which allows the homeowner to choose between contemporary, matte and honed tiles or more rustic and textured cleft tiles. Slate naturally has more texture than other stone tiles even when honed. It may have a layered flaky look while other stones are smoother even when tumbled. Slate can range from colors that have little variation to colors that have extreme amounts of variation in one lot. Marble and granite may also have similar amounts of variation in color but with more pattern and veining than slate.
  
  

Installation

• Gauged, ground back slate tiles install identically to other natural stone tiles. Ungauged, natural cleft slate tiles, however, require more time and experience to install properly. Ungauged slate tiles may vary in thickness by as much as 1/4 inch between tiles and within one tile. Some ungauged tiles are much thicker on one half of the tile than the other, requiring the installer to even out the installation with thinset. Back butter every slate tile with thinset to produce a level floor.
  
  One benefit that ungauged slate offers over other stone tiles is the ability to choose the coloration of the tile that is most pleasing. Slate tiles can be installed with either side facing up, so if one tile has a more pleasing color on one side, it can be shifted around. Other stone tiles do not offer this benefit as they have ground, not finished, backs.
  
  

Maintenance

• Unlike most natural stone tiles, slate is nonporous. While marble, travertine, limestone and some granites will absorb water and potentially stain, slate does not absorb moisture. Slate does scratch easily, however, and these scratches can be very visible on the surface of the stone. Surface enhancing sealers will help to eliminate the scratches if desired. Slate's cleft face finish may make cleaning the stone more difficult than polished, honed and even most tumbled stones of other variety. Debris, mud, dirt and other materials can collect around the ridges and dips in the surface of the stone. Lightly sweeping the stone may not be enough to free most surface debris, and more deep cleaning may be required.
  
  

Other Concerns

• Slate tiles are formed from layers, which can be seen by turning the tile to look at its thin edge. Some of these layers, particularly the thin layers on the surface, are brittle and weak. For three months after slate has been installed and as it acclimates to its new home, these thin layers may chip and break off easily in a process known as spalling. Slate may therefore be extremely dusty, dirty and may produce what looks like mud when mopped for the first three months after install. While some green marbles may spall on prolonged contact with water, no other natural stone will require additional cleaning after the initial installation.