top of page


Confused about 'rectification', or unfamiliar with terms like 'back buttering'? Whatever your existing knowledge, this is a layman-friendly guide to all terms tiling related.

To access other topics in the Knowledge Centre, click the book icon below.

Quarry Tiles

Extruded tile, typically 13 to 19mm thick and 150mm square (or larger), manufactured from shale or natural clays. Usually unglazed, they are generally available in terracotta, brown and black.  They are rarely used on walls, but can occasionally be seen on countertops.


A mineral occurring naturally in more than a dozen common types, including amethyst and onyx.

Quartz Tiles

Tiles described as “quartz tiles” are not natural stone, but are manufactured using quartz sand, resin, and mirror flecks.  The mixture is heated to an extreme temperature to create the finished articles.  The better quality tiles have a high natural quartz content, typically 90% or more.

Ramp Test

One of the standard methods of testing the slip resistance of tiles and other floor coverings (see Pendulum test).  This involves the testing of flooring samples with a surface that has been ‘contaminated’ with, for clean water, a soap solution, oil or other substance.  An individual walks forwards and backwards on this sample that is set at increasing angles of slope.  The average angle of inclination at which the walker slips enables the calculation of the coefficient of friction (CoF) for the flooring material. The UK Slip Resistance Group (UKSRG), in conjunction with the Health & Safety Laboratory (HSL) and the British Standards Institute (BSI), have developed their own version of the ramp test.

Outside the UK, recognised DIN standards offer two versions of the test, which classify slip resistance for each tile material/type: DIN 51097 Barefoot Ramp Test, for wet and barefoot conditions; and DIN 51130 Shoe Shod Ramp  Test for safetybooted feet on a lubricated surface. Barefoot testing classes are: A (12° to 18° slope); B (>18° to 24°); and, the highest rating, C (>24°).  The shoe shod classes are: R9 (6° to 10° slope); R10 (10° to 19°); R11 (19° to 27°); R12 (27° to 35°); and the top-rated R13 (>35°).

Reaction Resin

Any resin involving two or more components including a synthetic resin and mineral fillers or additives and which requires a chemical reaction to harden.  Typical examples would include polyurethane and epoxy resins.


Tiling adhesives are available in two forms: powder and ready-mixed. Powder adhesives, which require the addition of water, are available for both floor and wall use but ready-mixed adhesives are generally only suitable for use on walls.  This is due to the essential difference between their characteristics: powders set through a chemical reaction brought about by adding water, while ready-mixes set by losing the water already contained within the mixture.  In use, a ready-mixed adhesive takes at least 24 hours to set before grouting, while 16 hours would be normal for a powder, or as little as two hours for a rapid-setting adhesive. 


Although ceramic tiles exit an extruder or press with virtually identical dimensions, the drying and firing processes cause shrinkage that can vary from tile to tile. In order to assure users that tiles are consistently sized, they can be rectified after firing. This consists of machining each tile, with saws or grinders, to ensure that all tiles within a batch are the same size.


This process involves removing the edges of the tile to give a cleaner finish and meet size specifications. Tiles cut in this manner have a uniform size thereby reducing grout joints to a minimum.

Rectified Glazed Porcelain

These are porcelain tiles that have been cut during the manufacturing process to meet the exact sizing requirements. They are much more aesthetically versatile, coming a variety of finishes including matt, glazed, metal effect or stain.


Non rectified tiles have natural, uneven pressed edges that may vary slightly in size and require a wider grout gap.

bottom of page