Glossary of Product Terms

Porcelain Tiles – The major difference between porcelain tile and ceramic tile is how it’s made. Both tiles are made from a clay mixture that’s fired in a kiln, but porcelain tile is made from more refined clay and it’s fired at higher temperatures. This makes it denser and more durable than ceramic tile.

Exterior Porcelain Tiles – The most significant difference is that exterior porcelain is the thickness, which is usually a minimum of 20mm as a result these products feature expetional durability and breaking strength.

Water Absorption – Usually expressed as a percentage, this reflects the amount of water absorbed by a tile. Porcelain tile is categorised as “impervious,” which means it has a water absorption rate of less than 0.5%.

EN standards define tiles by their water absorbency.

<0.5% = B1a (very low water absorption)
0.5% <3.0% = B1b
3.0% <6.0% = B11a
6.0% <10% = B11b
>10% = B111 (high water absorption, normally a wall tile)

Each classification has a technical advantage depending on the end use.

PEI Rating – Applies to glazed floor tiles and is a testing system to rate the wear and tear due to friction.

PEI 1 – Very light domestic traffic usage – such as residential bathrooms or bedrooms. These Tiles are not recommended for any area that will have any constant or heavy foot traffic.

PEI 2 – Light domestic traffic usage – tiles suited to use in the home, this tile should not be used in areas such as kitchens, entry ways, stairs, or areas with heavy traffic.

PEI 3- All moderate traffic domestic use – suitable for all areas of the home, This tile should not be used for commercial use.

PEI 4 – Moderate to heavy traffic, tiles suitable for residential Interior Floors, and light commercial applications, such as restaurants, lobbies, etc.

PEI 5 – Heavy Traffic usage -These Tiles can be used on all residential interior floors, and all heavy commercial applications, such as airports, shopping malls, supermarkets, etc. This tile is an excellent choice for Industrial applications where extreme durability is required.

Rectification – A product that has undergone a further manufacturing process , where the tile is cut after the firing process, to produce clean edges on all sides.

Slip Rating / Anti Slip/R- Rating

Ramp Tests
The German ramp test is used to generate the DIN 51130 R ratings and DIN 51097 ABC ratings used commonly in North Europe. These tests can only be carried out in a laboratory, so does not allow in-situ testing of materials.

R Ratings (DIN 51130) – This is a shod foot test which uses oil as a contaminant. These results are interpreted into 5 groups, R9 to R13. R9 being the slipperiest and R13 being the least. Please note: R9 is not suitable for areas requiring slip resistance. The are no such categories as R1 – R8.

ABC Ratings (DIN 51097) – This a wet barefoot where a soap solution is applied as a contaminant, the results from this test are placed into three categories:

  • Class A – Dry areas including dry changing areas, dry barefoot corridors
  • Class B – As A plus pools surrounds, communal showers, pool beach areas, wet change areas
  • Class C – As A and B plus pool surround inclines, walk through pools, Jacuzzi floors and seats, inlined pool edges and steps

BS796 Part 2 4S96 pendulum test method.

Test result Slip risk
65+…………………………..Extremely Low


Natural Stone
Rock formed naturally over time and by different processes into three kinds of rock type: igneous, sedimentary and metamorphic. The rock is extracted from the ground, cut and processed into tiles.

Solidified magma or lava formed after volcanic activity. Extremely hard. Examples: granite, basalt.

Metamorphism is the transformation of one rock type into another, brought about by heat, pressure or chemically active fluids. Examples: Marble (originally limestone or dolostone), slate (previously sedimentary shale or mudstone).

Weathering of existing rocks produced sediment which settled in layers and gradually ‘lithified’ (turned to stone) by compaction and cementation. Examples: limestone, travertine.

Basalt – Formed from molten lava, you can see tiny bubbles that were made when it was cooling into the solid stone that it has become.  Cool, smooth and dark, basalt is incredibly hard-wearing and suitable for most areas.

Granite – Once molten like lava, then squeezed and forced up from the very centre of the earth, granite solidified millions of years ago. The stone is mainly made up of mica, quartz and feldspar. It is these minerals that give granite its characteristic glints of crystal, and the many variations in colour. Granite is dense, strong and durable.

Limestone – Sedimentary layers of shells and micro-skeletons were deposited on the seabed, and then compressed into the hard rock you see today.

Marble – Marble is a crystalline, metamorphic rock that was once originally limestone. Great pressure transforms the limestone into a hard, crystalline rock that can be worked and polished. White in its pure form, impurities form veins of many colours and make each slab unique.

Sandstone – Sandstone is a sedimentary rock composed mainly of sand-size mineral or rock grains and is composed for the most part of quartz (which lends the stone its glossy lustre).

Slate – Enormous pressures involved in the movement of the earth’s tectonic plates, realigned the minerals mica and chlorite in shale and mud stone, to form the smooth flat layers of slate found today.

Terracotta – Clay taken from the earth is stripped of physical and chemical impurities. The resulting balls of clay are then shaped and cast individually into frames where they are left to dry in the sun before firing.

Travertine – Travertine is a form of sedimentary limestone, made from compressed deposits left by calcite-rich hot springs which became, over millions of years, almost like a river frozen in time. The stone is usually pale with some inherent pits and holes which are the result of its creation. There are three different grades of travertine, dependent on the quality, thickness, impurities, and sizes of the pits and voids. Grade 1 is the best, and, as with all things, is worth paying extra for a better quality stone that will last for years if installed and maintained correctly.