Do you know your porcelain from your PEI rating and your sealant from your spacers? Our ever-evolving glossary of tile terminology helps explain some of the words and phrases you might hear or read about when you’re choosing tiles.

Tile Terminology

20mm tiles

2cm deep tiles are very strong, easy to install and can be removed easily, making them ideal for gardens. They are great to coordinate from indoors to outdoors.

Abrasion Resistance

Abrasion resistance is the ability of tiles to withstand being worn down by friction and rubbing.


Absorption is the amount of water a tile absorbs. This is shown as a percentage made up of the ratio of the weight of the dry tile to the weight of the absorbed water.


Tile adhesive is used to fix tiles to the floor or wall. Adhesives can be flexible, waterproof or specifically for porcelain tiles.

Antique finish

This describes ageing/distressing methods used to imitate a worn look on stone.

Bevelled Edge

A tile with a bevelled edge will not be completely flat but will have an angled edge for safety, to prevent wear resistance or to simply look nice. Commonly found on metro or subway tiles for a more 3D effect.


Nothing to do with Digestives, this tile terminology is the main clay body of the tile that provides strength.

Brick Bond

A brick bond tile pattern is the same used with house bricks, where the joins are staggered. This is only suitable for tiles under 30cm x 60cm.


Most tiles will have a slight bend due to the heating and cooling processes during production. This is called bowing or warping. It is less noticeable on smaller or square tiles but more obvious in larger rectangular tiles.

Brushed Finish

Brushed stone tiles have a smooth finish with a worn look that gives them a more natural or rustic appearance. This is achieved by sweeping a diamond-tipped wire brush across tiles such as limestone, sandstone and slate.

Bullnose or “RE” (Rounded Edge)

Bullnose tiles have characteristic rounded edges to give a softer look than sharp angles. They are used for edges or trims, to cover corners or to frame the perimeter of a tile design.

Butt Joint

Butt jointing is where tiles are laid closely together to create a small grout joint, commonly next to a wall. The usual spacing should be more generous to allow for grout.


Calibrated tiles meet the manufacturer’s calibre range, with less dimensional variation than natural tiles without mechanically finished edges.

Ceramic Tiles

Ceramic tiles are usually glazed, making them usually only suitable for walls, but there are some that can be used on floors. Ceramic tiles are man-made from clay, fired at a lower temperature and have greater water-absorbency than porcelain. See our comparison table for more information.


Chevron tiles are cut with their short edges at an angle and should be supplied as left and right. They are used to create diagonal patterns.

Cove base tiles

Cove base tiles are often used at the base of a tiled wall instead of a tile baseboard. They have a flared edge to create a seamless and watertight transition between the floor and the wall.

Crackle Glaze

Crackle glaze tiles have a glossy surface with a cracked appearance. This used to be formed by thermal shock, freezing tiles immediately after going in the kiln to shrink the glaze, but modern crackle tiles are created with a specific glaze that shrinks in the drying process.

Crackle glaze tiles MUST be sealed so they have an impenetrable barrier against dust, grout and moisture. Seal before and after grouting for the best results.


Cracks that occur due to temperature change and vibration are a natural characteristic of glazed tiles.


A technique used with Travertine stone where the tile face is at right-angles to the main direction of the veining. See vein cut.

Cushion Edge Tiles

Also known as non-rectified tiles and soft edge tiles, cushion edge tiles are not cut to size after firing, and have more variation in size. These tiles are usually glazed, patterned or smaller where cutting the tile would be detrimental to their appearance. They are also not as sharp and prone to chipping as rectified tiles.

Decor tiles

Decor or decorative tiles usually have a pattern that can be bold or subtle and can often be found alongside a neutral or plain tile in the same range.

Decoupling Membrane

A decoupling membrane is a type of matting made from plastic or fabric that helps prevent newly laid tile floors from cracking or lifting if the substrate beneath them cracks or moves. These are commonly found in new build properties where the foundation is settling in. You can use a decoupling membrane between tiles and underfloor heating as a precaution against cracks from the heat.

Encaustic tiles

Encaustic tiles are made of ceramic, with their patterns made up of different colours of cement and dye rather than a glaze on top. They commonly feature two colours but there can be more.

Epoxy Adhesive

Epoxy adhesives are super strong, created by polymerizing two starting compounds, the hardener and the resin. These adhesives have exceptional adhesion, chemical, heat and water resistance, and electrical and mechanical insulating properties.


Often mistaken for a crack in the tile, a fissure is a thin line of mineral veining that usually contrasts with the stone’s base colour.


Large and thick stone tiles used internally or externally or internally.

Flemish Bond

Flemish bond is a tiling style where rectangular and square tiles are laid together in alternate patterns to achieve a modular appearance with lots of interest.

Free Length

This tile-laying format is used when the tiles have the same width but varying lengths.

Full-Bodied Porcelain/Fully Vitrified

Full-bodied tiles have their main colour and/or design running all the way through the body. They are made from a single layer of porcelain and have a water absorption rate of 0.5%.

Glazed tiles

Glazed tiles go through a second firing process to gain a protective coating of liquid glass, allowing them to be printed with colours and designs using inkjet technology.

Gloss tiles

Gloss tiles have a shiny surface and can be porcelain or ceramic. They are easy to clean, making them ideal for kitchens and bathrooms, and reflect the light – great for creating the illusion of more space in smaller rooms.


Grout is the finishing touch to your tiles. Not only does it complete the look, but it also acts as a barrier to dirt and germs, and as a buffer to limit any movement or expansion and contraction caused by temperature changes. Use a matching colour for a seamless look, or contrast to make the tiles really stand out.


This is a tiling method usually used with metro tiles to create a ‘v’ pattern by laying tiles perpendicular to each other. These can be at 45- or 90-degree angles.

Honed and Filled

This is where the tile surface has been given a smooth finish by filling any holes with resin or by using a high-speed machine.

Ink Jet Tile Printing

Once upon a time, coloured rollers would create patterns on tiles, but Inkjet printing is now used to produce vibrant, intricate patterns on tiles, or realistic wood effect designs.

Lappato or Semi Polished Finish Tiles

When tiles are first made, their surfaces are slightly textured. These are usually polished down, but a lappato or semi-polished tile is only polished 50% to give a lovely blend of smoothness and texture.


Lippage is the allowance of how much one tile can be slightly further off the wall/floor than another. The British Standard BS5385-3 sets this out as a tolerance of 1mm for joints less than 6mm wide and 2mm for joints of 6mm or more. Lippage is more obvious with larger, rectified tiles, due to the variation in flatness. This can be minimised by not laying large tiles in a brick bond or staggered pattern.

Listel or Listello

An exotic-sounding item of tile terminology,  a listel or listello is a border tile used as a design feature, or to separate two designs, or tiles and wallpaper/paint.

Light Reflectance Value (LRV)

This is a key consideration if you’re tiling an area used by the visually impaired. Tiles have unique Light Reflectance Value ratings (LRV). If you need to distinguish two different areas or step edges, your tiles will need an LRV difference of 30% to make them stand out.

Matt Tiles

Matt tiles give a more neutral look than shiny gloss tiles. They are great at concealing dried water droplets, smudges and stains and don’t need to be cleaned as frequently as gloss.

Metro or Subway Tiles

Brick-style tiles are named after the underground stations they are often used in. Available in matt and gloss, patterned or plain in a variety of colours.

Mitred Tiles

Mitring is where a tile is cut at a 45-degree angle along an edge, to remove the ‘biscuit’ or underside of the tile

Mosaic Tiles

Mosaic tiles are small pieces of glass, stone or plastic that create a lovely mosaic effect. They usually have a mesh backing to make installation easier. Mosaic tiles are great for feature sections or to create a mural.


Nippers are small pliers that are great for detail when cutting tiles.

Nominal Size

This term describes the approximate thickness of a tile.


Unlike rectified tiles, cushion edge or non-rectified tiles are not cut to size after firing and have more variation in size. The softer edges mean they are not as sharp and prone to chipping as rectified tiles. These types of tile are usually glazed, patterned or smaller where cutting the tile would be detrimental to their appearance.

Non-Vitreous Tiles

Non-Vitreous Tiles absorb 7% or more moisture, so they are only suitable for indoor use. Semi-Vitreous Tiles absorb from 3% to 7% moisture, and Vitreous Tiles absorb less than 3%.


These are slight imperfections on the body of a tile that resemble pinpricks

Polished Tiles

Polished tiles are usually porcelain or natural stone, mechanically polished with a fine abrasive diamond wheel for a super shiny finish.

Porcelain Enamel Institute System (PEI)

A commonly requested item of time terminology, PEI Ratings are used worldwide to grade the resistance to wear and tear of the finish of floor tiles.

PEI 0 – Wall tiles only

PEI 1 – Light domestic traffic areas where you wear slippers or go barefoot, such as bedrooms and ensuites

PEI 2 – Moderate domestic traffic areas such as bathrooms

PEI 3 – All domestic use

PEI 4 – Intense footfall – great for the home and ‘light’ commercial spaces such as offices, bars and restaurants

PEI 5 – Heavy footfall areas such as supermarkets and airports

Porcelain Tiles

Porcelain tiles are made with white clay, feldspar (rock-forming tectosilicate minerals) and sand. Compared to ceramic tiles, they are more hard-wearing, absorb less water and can be used on floors and outdoors. On the downside, they are harder to cut and are not available in as many design choices. See our comparison table for more information.

Pendulum Test Value (PTV)

The Pendulum Test Value is the result of a test for slip resistance where a rubber footed pendulum is swung over the surface of a floor or tile to record the friction. Anything graded 36 or more is considered Anti-Slip.

R Ratings

One of the most commonly asked for tile terminology, R Ratings are a measure of anti-slip properties. The ‘R’ stands for ‘ramp test’ and the number is the anti-slip grade, from 9 (slight) to 13 (strong).

R9 – Ideal for domestic environments and, if made from porcelain, commercial environments where anti-slip properties are not really required.

R10 – Ideal for kitchens and bathrooms, and as external floor tiles (porcelain only) and lighter use commercial tiles.

R11 – Suitable for both dry and wet environments. Can be used in bathrooms, kitchens, hallways and living rooms. They are also suitable for office floors and for exteriors.

R12 – Great for exteriors, kitchens, bathrooms and hallways, and commercial areas such as communal showers and lavatories, poolsides and changing rooms to hotel foyers, shopping centres and airports.

R13 – Areas frequently exposed to water such as swimming pools, spas and patios

See our handy blog post for more information.

Rectified Edges

A rectified tile is made from porcelain or ceramic tile and has been cut after the firing process rather than before, giving a sharp, clean edge that will need less grout and create a more seamless look.


This is where a tile has been given the effect of lamination to recreate the look of slate and sandstone.

Rustic Edge

A more random and less uniform tile edge that creates a more ‘handmade’ look.

Satin Finish

A straightforward tile terminology term. These tiles have a subtle shine which also gives a little reflection too.


This layer may be applied in new builds over concrete or insulation. Screed is traditionally made from cement and sand.


Sealants should be used with materials such as grout, natural stone and quarry tiles to prevent water absorption and debris.


Semi-Vitreous Tiles absorb from 3% to 7% moisture. Vitreous Tiles absorb less than 3% and Non-Vitreous Tiles absorb 7% or more moisture (so they are only suitable for indoor use).

Shade Variation

Some tiles will have a slight variation in colour. This could be to create an effect like wood or watercolours. However, the variation may be accidental between batches, which is why we always recommend to over-order slightly so all your tiles are from the same batch. If you do have to buy more and they are different, mix the two batches together.

Slip Resistance

Slip resistance means how much grip a tile offers, and this is measured with a PEI grade or an R rating. The higher the rating, the more anti-slip the tiles are.


These small plastic pieces are used to evenly separate tiles and are removed once the tiles are in the right place.


Tiles or a sheet of material behind a sink or hob to protect against splashes and stains from liquids and food.

Splitface Tiles

Splitface tiles create lots of texture and interest in a room. They are made by joining together small pieces of natural stone into single tiles which can then be joined together to create a feature wall.


A tile can sometimes be slightly raised off the floor or wall than another, called ‘Lippage’. The British Standard BS5385-3 sets this out as a tolerance of 1mm for joints less than 6mm wide and 2mm for joints of 6mm or more. Due to the variation in flatness, lippage is more obvious with larger, rectified tiles, but this can be reduced by avoiding a brick bond or staggered pattern.


A membrane for waterproofing applied before tiling to a shower enclosure. This protects the underlying substrate from penetration by water penetration. Especially useful in wetrooms.

Tile Density

Tile density calculations are useful for determining whether a tile can be used for a wall or floor. Materials like clay have a lower density making them ideal for walls, whereas heavier porcelain is better for floors. As well as the materials it is produced from, density also depends on how the tiles are compressed and the temperature it is fired at.


This usually refers to Travertine which has characteristic surface holes and pits, left open by being unfilled.


Upstands are tiles that act the same as a skirting board. These are commonly used in kitchens around counter-tops.


The natural mineral lines found in stone, particularly in marble. Marble-effect tiles have printed veins that can vary from subtle to striking.


A technique used to give Travertine tiles or slabs a banded appearance, where cuts are made in favour of the natural vein. See cross-cut vein.

Vitreous Tiles

Vitreous Tiles absorb less than 3% of moisture. Non-Vitreous Tiles absorb 7% or more, so they are only suitable for indoor use. Semi-Vitreous Tiles absorb from 3% to 7% moisture.


Ceramic and porcelain can shrink, bow and warp when fired. This can be more exaggerated with larger tiles, so it is best to avoid brick bonding.

Ceramic Versus Porcelain Tiles

Ceramic Porcelain
Best used for Indoors
Walls and floors
Domestic interiors
Commercial interior walls
Low foot traffic areas
Floors, some walls depending on the weight of the tiles
Commercial properties
Areas with high foot traffic
High moisture level areas e.g. wet rooms
Properties Softer and less dense Harder and denser
Made from Red, brown or white clay White clay, feldspar and sand
Fired at a higher temperature
Pros Easier to use
Great choice of designs
Less water absorbed
More hard-wearing.
Cons May crack in cold weather Less choice of interesting designs
More brittle
Price More reasonably priced More expensive
Ease of cutting Easy to cut Can be harder to cut


We hope our tile terminology guide has been helpful! If we’ve missed something out, please get in touch, we’d be happy to explain and add it to the list!