Outdoor Tiles

When dealing with outdoor areas, it is impotant to evaluate weather the area is completely outdoor or partially covered. A completely outdoor area is an uncovered area that is completely exposed to the elements. A partially covered area is a covered area with exposed sides (e.g covered patio or garage).

Recommended PEI rating: 4 or above




Tile Size

Tile size is not really as much as a concern here as tile finish.

Tile Finish

In outdoor areas, a tile with a significant level of slip resistance is required. A tile’s slip resistance is specified by it’s COF( Coeffiect Of Friction) rating, however, there are no international standards regarding the COF rating and outdoor applications. Typically, unglazed or rustic finish tiles will be more ‘non-skid’ than semi-polished or polished tiles. Regardless of the tile, keep in mind that water, or any other liquid, will always make a tile more slippery. Also, extremely non-skid or outdoor type products tend to be more difficult to keep clean since the more ‘non-skid’ a tile surface is, the more difficult it will be to maintain.

More on Slip Resistance

Although there are no international standards for slip resistance, there are several independent bodies that have guidelines for this. The skid resistance scale is used to determine the degree of slippage on a tiled surface. While assessing different tile surfaces, wet and dry conditions along with the speed of the subject are monitored. Also, the required force to move that subject and the angle of the tiled place are considered too. The Ceramic Tile Institute identifies tile in the following three categories:

  • Slip Resistant: Coefficient of friction is 0.60 or greater (wet). Meets or exceeds general safety and health regulations, ADA and OSHA requirements.


  • Conditionally Slip Resistant: Coefficient of friction is 0.50 to 0.59 (wet). Meets or exceed general safety and health regulations and OSHA requirements.


  • Questionable: Coefficient of friction less than 0.50


It is useful to understand the method of measurement in order for this to have technical meaning. In the US, they ASTM 1028 sled method where a 50-pound weight is placed on a sled with a special material (to represent a shoe sole) contacting the tile and it is pulled by an operator using a fish-scale. It is a dry measurement although it can be performed wet with water for investigation. The pull force needed to just start the sled moving, divided by the 50-pound weight determines the COF. Example: if it takes 30 pounds of pull to start the sled, divide this by 50 and you get 0.6, just enough for the ADA (American Disability Association) recommendation.

The DIN classification for tile slippage

DIN, the German Institute for Standardization classifies tile slippage within the DIN 51130 set. In this set, the various working areas are classified in five groups, according to the degree of slippage. To determine in which of these groups a material should be classified, it is applied on a surface that is gradually sloped. A person wearing shoes walks up and down the slope until he starts slipping. The value in degrees of the slope reached before he starts slipping determines the classification of the material in class. Here are the ratings:

  • Rating R9: Suitable for a less than 10% slope (minimal friction)
  • Rating R10: Suitable for a 10 to 19% slope (normal friction)
  • Rating R11: Suitable for a 19 to 27% slope (normal friction)
  • Rating R12: Suitable for a 27 to 35% slope (high friction)
  • Rating R13: Suitable for slopes more than 35% (very high friction)

*Sources: Tile Coucil of North America, Build Direct