How is Porcelain Tile Rated for Moisture Absorption?
Other than hardness, a particular and important consideration for porcelain tile
is moisture
absorption. The American National Standards Institute (ANSI) has developed a
rating for
moisture absorption by tiles. This rating is actually a procedure to test a
tile�s permeability
to water. It consists of boiling the tile in water and measuring its gain in
weight from the
original dry state.
Water absorption rates are a measurement of how much moisture a specific type
of porcelain
tile is likely to absorb on an ongoing basis. Some types of tile may crack if
the moisture
penetration is too high. Descriptions of the types of porcelain tile most
suitable for your project
comprise of four ratings, and are classified as under:
Non-vitreous (Low dense)
Tile with water absorption of more than 7.0 percent
Semi-vitreous (Medium dense)
Tile with water absorption of more than 3.0 percent,
but not more than 7.0 percent
Vitreous (High Dense)
Tile with water absorption of more than 0.5 percent,
but not more than 3.0 percent
Impervious (Extremely dense)
Tile with water absorption of 0.5 percent or less. This
is where porcelain tile is categorized
Reflecting the density of the tile body, ceramic tile are also classified by
their water absorption
rate apart from the resistance to wear and tear. The water absorption rate is
directly related with
the suitability of the various types of tile for interior or exterior
applications. For exterior
applications, the selected tiles must have a very low water absorption rate,
especially in climates
subjected to rainfall, freezing and thawing cycles. A low water absorption rate
also enables a tile
to absorb food or beverage stains on a lesser percentage. This is usually a porcelain
tile, which
has a moisture absorption rating of less than 0.5 %.