Author: Damian Cannon

30 Nov 2016
encaustic-2

What are encaustic tiles?

Encaustic tiles are ceramic tiles in which the pattern on the surface is not a product of the glaze but of different colors of clay. They are usually of two to as many as six colours. The pattern appears inlaid into the body of the tile. Typically they are square and less than 20 x 20cm in size.

porto
Modern ink-jet emulation of a selection of Portuguese encaustic tiles.

Encaustic is Ancient Greek meaning “burning in” which was also applied to a process of medieval enameling. Victorians thought that the two colour tiles strongly resembled enamel work and so called them encaustic. Despite the error, the term has now been in common use for so long that it is an accepted name for inlaid tile work. In both medieval times and in the nineteenth century Gothic Revival, tiles were most often made for and laid in churches. Even tiles that were laid in private homes were often copies of those found in religious settings. Encaustic tile floors exist all over Europe and North America but are most prevalent in England where the greatest numbers of inlaid tiles were made.

encaustic-4
Encaustic tile moulds.

Encaustic tiles are now more of historic interest than anything else. Although there are some demonstration production lines in living museums, the process is no longer used widely.

There are a very few encaustic tile makers these days and studios in the UK, US, Australia and Morocco are prominent. They use a two-part moulding process. The ‘inlay’ colour is moulded first. For multiple colours, a mould with cavities for each colour is used and the individual colours are filled carefully. This coloured clay is then placed face-down in a mould that is backfilled with the body colour. The tiles are then fired.

encaustic-5
Pouring the second layer of clay into the body then scraping smooth.

These days modern digitally printed ink-jet tiles are produced to emulate the look of encaustic tiles. These are often used for feature walls around fireplaces, kitchen and bathroom spashbacks, small wet-room walls or floors like showers or guest toilets.
encaustic-2
Modern ink-jet emulation – 16 tiles printed on one 60×60 body.

24 Nov 2016
411

How to make more profit by selling better tile adhesive.

411

In our disclaimer on our tile boxes it says “Ask your supplier to recommend the correct adhesive, curing time and cleaning materials.”
So…when your customer asks you to recommend a suitable adhesive (and even if they don’t!) look at the tiles that they’ve selected and in your best professional voice say:

“Well, these are 1st grade tiles, they’ll last forever if they’re installed properly, you should use this adhesive.” 

Point them towards your premium brand. Then go on to recommend your best grout and cleaning products. Also, always make sure that your customer is buying the recommended extra 10% to allow for breakages, trimming and spares.

The beauty of this approach to selling is that you’re not selling your customer short. On the contrary you’re offering the best professional service. Would you use cheap adhesive, I certainly wouldn’t. The benefit is that your customer leaves with a higher opinion of the tiles they’ve bought which means that they will talk about them and in all likelihood be back for more… and you’ve increased your profit by more than 10%! Plus, you can be confident that by using the best adhesives there’s far less chance that the customer will return with a complaint.

This upselling technique works!

15 Nov 2016
d501a19a-8b23-4597-b175-c548ba221ab1

What is Polished Porcelain and What is Nano?

The dense, hard surface of porcelain has made polishing a viable alternative to a glazed surface. This means that a tile can be fired, then a polished creating a shine without a glaze.

However polished porcelain may need sealing, where ordinary glazed tiles do not. Unsealed porcelain can attract stubborn stains and can become brittle when in contact with chlorinated water and acids.

When porcelain is first made, it is not absorbent, but the polishing process for making the unglazed surface shiny cuts into the surface, leaving microscopic pinholes exposed and prone to absorbing stains, in the same way as natural stone tiles. Unless they have a suitable, long-lasting treatment applied by the manufacturer like nano, polished porcelain tiles will need sealing. Porcelain sealants are either solvent-based or water-based. Water based sealants are cheaper, but don’t last.

Porcelain tiles with a nano treatment are more dirt and stain resistant, glossier and have more intense colour. Nano treatment is more complex than you might have thought. It consists of applying two different compounds up to ten layers deep to the surface of the tile, polishing between each application and then firing again at 1250ºC.

Here are two microscope images of a porcelain tile surface before and after nano treatment.


A nano polymer compound is pressed into the pinholes of the polished porcelain tile surface. This consists of very light and hard organic nano particles ranging in size from 5nm to1µm. The surface is then polished and a second layer is applied, polished again and a third layer applied. The particles are smaller than the tiny pinholes and cracks in the tiles so they fill these gaps and these pores become permanently sealed.

The second compound applied is a solvent flourine polymer then the tile is polished again. Flouropolymers are characterized by a high resistance to solvents, acids, and bases. With repetitive plating, applied through high pressure sanding and polishing, the nano particles combine with the tile substance to form an organic nano film with a high density and stability, which achieves the distinguishing characteristics of nano treated tiles. Generally at least six layers of polymer application and polishing cycles are completed then a final water wash before high temperature firing.

The technique of application, polishing and firing ensures that the nano particles polymerise (chemically bond) evenly on the surface of the tiles. The high surface sheen of nano tiles creates a protective layer so dirt cannot penetrate the tiles and they are easier to keep clean. The granular material of the protective layer enhances the tiles’ durability and slip resistance making them suitable for both domestic and commercial applications and after firing have a hardness equivalent to that of granite.

But it’s not just a long process, it’s tricky too. The specially designed polishing heads must operate at an ideal temperature of between 35ºC and 70ºC, they must also be carefully aligned to move consistently over the surface of the tile polishing each part with the same even pressure. The amount of compound applied to the tile must also be very finely controlled to ensure even distribution of the particles.

Our Classic Super White, Super black and Ivory tiles are all rectified, nano-treated polished porcelain. View brochure here.

09 Nov 2016
5005640150

What are Coefficients of Expansion and why are they important?

5005640150

A coefficient of expansion is a measure of how an object expands when exposed to heat or water. It’s important with tiles because unless you understand the principles and apply preventative measures when installing, tiles will expand and crack or lift causing floor failure.

Tiles expand for two reasons: being heated and absorbing water. These are respectively defined by the coefficient of thermal expansion (CoE) and the coefficient of moisture expansion (CME). The thermal coefficient is the amount of expansion (or contraction) per unit length of the material resulting from a change in temperature. In the tile industry the moisture coefficient is normally expressed as a percentage change in size after immersion in water. In tiles the effect of moisture expansion is around ten times larger than that of the coefficient of thermal expansion.

With tiles moisture expansion is commonly called ‘irreversible’ because once water is absorbed in the microscopic holes in the tile there is really no way for it to escape, especially with glazed tiles which are effectively sealed from above. In addition tiles also experience hydration, the chemical capture of water molecules in the tile body. Moisture expansion in tiles is the primary cause of ‘tenting’; when tiles push together and lift from the floor base. It is also the reason for delayed crazing.

The coefficient of moisture expansion is fundamental to the  design of movement joints, the proper installation of which will prevent tenting and cracking. This is even more critical in areas exposed to moisture such as bathrooms and outdoor spaces.

If the CME is a percentage multiply by 10 to give expansion in mm per metre. This can be used to calculate adequate movement joints. But 10% extra should be added.

Class Tile type             Water absorption          Expansion
B1a Porcelain                      < 0,5%                       5 mm/m
B1b Gres porcelain          0,5 – 3%                      30 mm/m
B1b Ceramic                     0,5 – 3%                      30 mm/m
B2a Ceramic                        3 – 6%                      60 mm/m
B2b Fired clay                     < 10%                     100 mm/m

Note the huge difference between possible expansion of real porcelain to fired clay tiles like Terracotta.