To seal or not to seal porcelain tiles

The question to seal or not to seal porcelain tiles is becoming one of the most asked question in the Nerang Tiles showroom. Customers are becoming more informed about different products and it all gets a bit confusing when you are deciding between natural stone, natural marble, natural timber or porcelain tiles.

We all know that natural products such as stone, marble and timber do require routine sealing but do porcelain tiles?

We couldn't answer it better than Scott Worthington from Aqua Mix via tiletoday.com.au. Check out his article below.

If you have any questions please give the experts at Nerang Tiles a call on 07 559 61 916.

Update
Since the writing of this article it is important to note there have been significant advancements in the manufacturing process of porcelain tiles. The advancements have drastically improved the quality, durability and aesthetics of porcelain tiles. 

Modern technological advancements in porcelain floor and wall tiles have made sealing almost all porcelain tiles unnecessary. The majority of porcelain tiles in the market are glazed. This means that they have less than 0.5% porosity and do not require sealing. In fact, only specialized sealers are suitable as most will not penetrate the glaze or be absorbed by the glazed porcelain tile. 

For more information about the qualities and benefits of glazed porcelain tiles see here.

The question of sealing porcelain is fast becoming one of the most asked in the industry. To fully understand the answer one must know a little about the history and make up of porcelain tile.
 
What is Porcelain Tile?
Porcelain as we know it today was first pioneered in Italy by several notable companies. Porcelain is made from a more pure blend of high quality clay than used in “normal” ceramic production, utilizing predominantly china or porcelain clays. These have high silica content and result in materials that have all of the characteristics of silica itself once fired, namely low water absorption, high chemical resistance, high abrasion resistance, and good overall hardness.
 
The pioneers of this technology recognized this high performance and marketed it accordingly with porcelain becoming the benchmark. One of the most accessible technical features used by the marketers to highlight this high performance aspect was water absorption. The European standards (Tolerances ISO UNE EN ISO 10.545-3) set water absorption at less than 0.5%. In many cases the European manufacturers bettered this impressive standard with common water absorption being less than 0.1%.
 
So, with such low water absorption and with the clay being milled and spray dried to such small particle size distributions before pressing and then firing to over 1200 degrees Celsius, the resulting porcelain DID NOT NEED SEALING.
 
This should therefore be the end of the story. However it is not. There are now many types of porcelain, especially polished, that do absorb liquids and hence can benefit from sealing. Why is this so?
 
Porcelain Today
The reason for this change is simple. Today we have so many different kinds of porcelain, manufactured with different standards in different countries to meet varying pricing and performance demands. In contrast, originally a small select group working to a defined set of high performance standards manufactured all porcelains in Europe. By default it set the definition of “porcelain”. However this definition is no longer something that can be attributed to all products labeled porcelain. Consequently where in the past we recommended no sealing for “porcelain”, we now ask for more information about the particular porcelain before answering. The fact is that there are now many porcelains that have a rate of water absorption higher than the original standard thus requiring a sealer to perform properly. To ascertain if a porcelain will benefit from a sealer application do a simple water test. If after several minutes water is absorbed then the tile can stain and will benefit from sealing. In general it is the polished products that are the most applicable, especially some of the “honed” or satin materials that are being offered.
 
Which Sealers Work?
The unique composition of porcelain makes it a difficult product to seal. It has low water absorption and a very fine highly compressed crystal lattice making it difficult for many conventional sealers to bond. There are only two types of sealers that will successfully protect porcelain, Penetrating type products and also Floor Finishes.
 
Penetrating or Impregnators
These sealers cure and work below the surface of the tile. They typically leave the tile looking natural and have no adverse effect on the tiles coefficient of friction (slip resistance).
 
It is commonly thought that the most successful penetrating sealers for porcelain are solvent based rather than water. The rationale is the solvents have a smaller molecular structure than water making it easier for them to penetrate the dense porcelain surface. This is valid to a certain extent. However if the application technique of a premium water base product (such as Aqua Mix Sealers Choice) is modified to allow the sealer to dwell for longer than the resulting performance is superior to traditional solvent sealers.
 
With most sealer companies trying to enhance productivity and quality control it is however believed to be counterproductive to change the normal and recognized method of penetrating sealer application. Therefore companies such as Aqua Mix have developed specialised porcelain sealers.
 
These are at present solvent based as they allow high performance as well as no modification to traditional application techniques. These new generation solvent sealers are much improved compared to the traditional versions. Aqua Mix Pro Solv 10 for example is a water dispersible solvent. It is non-flammable, non-toxic and has very good vapor transmission. It will not yellow and can be safely applied in hot temperatures, as its flash point is very high. It is a premium sealer in that it offers high levels of stain resistance (especially against oils) and has a life expectancy of up to 10 years making it far superior to traditional solvents.
 
Floor Finishes
Polished porcelains hard, dense and often smooth surface makes the application of surface sealers almost impossible and is the reason why penetrating sealers, like Pro Solv 10 are the industry standard. However when a polished porcelain surface begins to scratch and wear, traditional restoration by way of wet polishing is in many cases not practical. This is where the application of a “synthetic polish” becomes a realistic alternative. However to get a surface coating to successfully bond to the porcelain surface, thermoplastic resins must be employed. Without this technology normal air cured coatings will not get sufficient mechanical bond.
 
An example of this technology is Aqua Mix StonEndure Sealer Finish. It utilizes state of the art thermoplastic resins that when buffed with a high-speed machine gains a high mechanical bond creating a durable sealer finish with a very high gloss, very close to the original. These types of products are designed to work in the same high traffic, high wear environments as the porcelain itself.
 
“My Porcelain Gets Dirty, therefore I need to Seal!”
This is a very common statement. However it is in many cases just not true. As I have mentioned above, the main reason for sealing porcelain is to stop it absorbing things that would eventually stain. However as these sealers are penetrating they do not offer any protection to the actual surface and it is surface soiling that this statement refers to in most cases.
 
Porcelain used to be all full body or homogeneous as it is often referred to. However there are many other techniques used today – glazed, roll feed, double charged to name a few. Moreover there are many different surface textures many of them created by the use of plastic dyes to press the tile body before firing. It is these textures that are more often than not the reason for the problems our statement refers to.
 
A common complaint is that when porcelain is used in a car showroom or garage, car tire marks are very easily transferred on to the tile, but not easily removed. The client then assumes that a sealer will remedy the problem. However in most cases it is the very fine surface texture, characteristic of most porcelain that is abrading the tire and lodging the rubber particles in the very small fine pores of the tile. It is a typical porcelain complaint. It is very often further complicated by the presence of small amounts of grout haze left on the tile surface after installation.
 
The solution to this problem is to clean and maintain the porcelain correctly rather than apply a sealer. Most porcelain cannot be maintained by wet mopping alone. The characteristic microscopic textured surface requires periodic cleaning with a heavy duty alkaline cleaner (for example Aqua Mix Heavy Duty Tile and Grout Cleaner) and an abrasive pad such as 3M’s Scotchbrite brand.
 
Conclusion
There is no doubt that the question of whether you do or do not need to seal porcelain is NOW a legitimate question. When porcelain was first created it was not. The only real questions then related to maintenance. However with the advent of different market requirements and the proliferation of porcelain manufacturers worldwide “porcelain” no longer can be defined by the same original technical and performance criteria. The name porcelain now encompasses a much wider range of performance characteristics and some of these can in no doubt be improved by the use of good sealers.
 
So the answer to the question “do I need to seal porcelain” is no longer a blanket NO!
 
The correct reply is “which type of product is your porcelain” and following some simple tests and discussion with your supplier, the answer should be revealed.
 

Source: Aqua Mix