The manufacturer’s recommendations on the setting material called for a 3/8 notch trowel for a 12-by-12 tile. As you can see, the type of back affects coverage and a larger notch or backbuttering may be needed.

This drill press set-up makes drilling holes with diamond bits in porcelain effortless. There are also water retaining rings made by several manufacturers if you wish to use a hand drill.
I want porcelain! Sometimes I wonder if a tile conversation with a potential purchaser starts any other way anymore. Well, the porcelain craze certainly has been great for the tile industry. No question porcelain tile is getting a continually bigger share of the market. Still, sadly, from many things we hear and even read, it continues to be a misunderstood product.

The definition of porcelain tile is simply that it has less than .5 percent absorption. That makes these tiles very strong and dense. Because they are so dense they can be left unglazed and used on the floor. As they have no glaze to wear out they will stay the same color and appear the same for generations to come. One of the misconceptions that persists is the durability of glazed porcelain. When a porcelain tile is glazed it is the glazed surface that takes the wear, not the body. There are glazed porcelains (porcelain tiles) on the market that are only suitable for light duty or residential. Granted, this is not the norm, but they certainly are not unusual to find. On the other side of the spectrum we see double-charged porcelain tile where the effects we typically have only seen in glaze tile are being created by the addition of pigments to the second layer and then fused into rather than on the body; double charging is more for the infusion of stain resistance than it is to infuse a different color.

This drill press setup makes drilling holes with diamond bits in porcelain effortless. There are also water retaining rings made by several manufacturers if you wish to use a hand drill.
Porcelain technology has come a long way with even more methods of production to create stunning visual effect under development. From a designer point of view; the best is yet to come. However, we are the installation community, the ones who have to make everyone's dreams a reality, no simple feat in many instances. If you have worked with porcelain tile for any length of time you know the workability can vary substantially between products. This is due the many variables in the production process while still staying in the prescribed range of under .5 percent. In this article we will explore a few ways that will hopefully make life a little simpler.

You cannot write an installation article without talking about thinset coverage and that is where we are going to start. As long as I have been doing this it never ceases to amaze me that some do not see the importance of this issue. You cannot believe what a difference this makes to the performance of the installation, even in instances where it probably should not have been installed in the first place. Time and time again we see failures where you can see all the ridges on the back of the tile. We do a demonstration to show the difference between full and partial coverage as part of our training classes. We can take any substrate you desire, give tile 100 percent coverage and carve a hole in the tile without cracking. Something we hear often is, "Well the instructions on the bag said use xx notch with xx tile." Instructions on the back of the bag are a guideline to give a general idea of what is recommended. The thinset manufacturer has no way of knowing what type of back the tile has which can drastically affect the size notch needed. Coverage of 80 percent minimum is the rule, not notch size; more is better.

This large tile cutter will cut a 24-inch porcelain tile on a diagonal. There are numerous large scoring type cutters on the market that will save a lot of trips to the wet saw.
There is also an always ongoing conversation about the need to back-butter, or flat trowel each piece of tile in addition to troweling the floor, primarily when you get into larger size tile. There is no argument that back-buttering provides a great value to any installation, it does offer superior performance. There are times when it may be necessary if the back of the tile has large cavities but if you can get the appropriate coverage by using the correct notch to trowel the floor you can save a lot of hours on installation. It should go without being said that a premium setting material should always be use with porcelain tile.

Cutting porcelain can be a challenge, especially if you want to score and snap the tile. Porcelain comes in a seemingly wide variety of hardness. But, there are many scoring cutters that will do the job even on textured porcelain. The ones that work best are on the pricey side typically and even then, some are better than others. We receive a lot of discontinued tile for our training programs so we always have a wide variety available. Before I had access to all these wonderful tools, while I was contracting, we would always run for the wet saw whenever we had a porcelain tile job. If I knew then what I know now, I could have made a lot more money in much less time. Do they work all the time? No, but I am hard pressed to think of more than a half dozen instances in the last six years where I could not score and snap a porcelain tile acceptably enough for a wall cut. In demonstrating these tools on a regular basis I can also tell you it takes a certain touch to be successful. People tend to score way too hard and take too much time before they snap the tile. I demonstrate scoring with a two-finger hold on the scoring tool and give the breaker a little slap to snap the tile. If you have a good wheel it works, try it. Speaking of cutting wheels, they are not all created equal either; that can be a problem all by itself.

This is a close-up of a cut in 24-inch porcelain tile. The cut is clean and chip free so it could be used in the field or for wall cuts.
Probably everyone's nightmare, based on the calls we get is drilling holes in porcelain. You can throw your carbide tools away when it comes to drilling porcelain; diamonds are a tile setter's best friend here once again. As many have found out the hard way, the quality of tools can be pretty dramatic when it comes to diamonds. Porcelain tile likes tools with lots of diamonds, and small ones. Bigger rougher more widely spaced diamonds in the rim may be great for fast cuts in brick or regular ceramic but when it comes to glass or porcelain more and smaller are better. Porcelain tile likes low even pressure when it is being cut. You can find a fair amount of difference in cutting speeds between blades. One thing all diamond tools do share is their love of clean water when it comes to long life. Having always been in a production environment, I never really played with the water I use on my tools that much; like everyone else, I needed to get the job done. Clean fresh water helps the saw cut cooler, faster, and longer. Always clean any residue from the tile and wipe dry before installing. When it comes to saws, bigger is better. 11/2 hp with a 24-inch straight cut and 18-inch diagonal is pretty much the standard if your serious about tile work, Quality tools last a long time; they may be more expensive on the front end but they avoid buying something twice. I would advise anyone who works with porcelain tile to get a good premium blade from a reputable manufacturer. If you have never tried one, it really makes a difference in speed and chip free cuts. Smaller saws are nice to have around and will cut porcelain tile, but it is hard on the saw and the blade. There are numerous tools on the market that make working with porcelain tile quick and easy.

When it comes to setting porcelain tile a few things come to mind. Narrow joints seem to be the rage these days. All tiles vary in size, some more than others. Porcelain tile like all ceramic products shrinks to size when it is fired in the kiln. Production equipment comes into play to a certain degree as newer equipment and technology has given manufacturers a much better ability to hold tighter tolerances. Quality control determines what goes in the carton you receive, regardless of equipment used in the manufacturing process. Size variation is inherent in all fired clay products. If your customer wants tight joints they should consider purchasing rectified tile, eliminating the risk of size variation.

When a ring won’t work to hold water around the diamond bit, this hole saw kit comes with an arbor that feeds the water right on the bit. This is a perfect setup for textured tile. You drill a pilot hole followed by whatever hole size you need in a second pass.
Rectified tile is ground after firing to insure uniform size, within thousandths of an inch. Tight joints also require a very flat floor. The bigger the tile, the flatter the floor needs to be. There are many who often comment that we the tile industry should require flatter floors. The flatness of a floor is determined by who puts the floor in and not by what we want. In the tile industry we are concerned with flatness. The standards for what is acceptable are set by the substrate trades, not the tile industry, we just put floors in or that is the theory. The recommendations of the tile industry are the same as those of the substrate trades, 1/4-inch in 10 feet for flatness with a maximum variation and no more than 1/16-inch in a one-foot area. If there is opportunity in new construction we can ask for flatter floors but they come at a cost to the owner. Self leveling compounds are great for remediation when floors need a little help and the money is available. The only downside to their use is the difficulty in accurately calculating the amount required.

Level is a good thing but it always cost more than flat. Using self levers is a commitment and once you start, you're committed. They do provide an outstanding substrate and I would use them at every opportunity. It would be wise to use a product from the same manufacturer you chose to provide the rest of the setting materials to avoid any compatibility issues. If self levelers are not in budget and some undulations are present in the existing floor, it makes the job simpler if the floor is flattened prior to installation. I have tried to flatten a floor by adding a little thinset to the tile while installing more times than I care to admit. It never did work very well; flat at one doorway and 3/4-inch higher at the other. If you have tried it you know what I am talking about. That is about all the space I have this month. Hope you find this helpful in your endeavors. Because we want to be your source and provide the most up-to-date installation related information available, we would like to encourage you to submit topics or questions that you would like to see in future issues. Please feel free to email the editor or myself with your interests and we will do our best to address your areas of interest.