Sand and cement installations were simple yet very effective and always provided a very flat floor. There was a skill level required to achieve successful installations. If you were not trained and skilled in the use of sand and cement you could be relatively sure the floor or wall would not last long enough to collect the check. I have read publications back into the early 1900s and even then, adequately skilled tradesmen were in short supply. This played a big part in the slow growth of the tile industry. Lack of qualified labor, hence, very expensive labor was the norm. This served as an impediment to growing the tile industry. With the desire to grow, necessity being the mother of invention, thinset was born. No longer was a 4-year indentured apprenticeship necessary to learn the basics of ceramic tile installation.
Thinsets were first developed in the fifties and sixties. Both the Tile Council of America and Henry Rothberg Sr., founder of LATICRETE International, held some of the original patents. In a short period of time, from after WWII, when all tile was mud set, to around 1970, when thinset was very common, the U.S. industry grew from 25 million to 250 million feet. The development of thinset removed the skill set required to work with sand and cement and started to make the installation process part of a knowledge rather than a skill quest. Sand and cement can be used anywhere adequate support exists; not so with thinset mortars. Some work well inside, some outside, and some but by no means all, both. Thinset may all look like sand and cement to you but the reality is those two basic components are only a small part of what’s in the bag. Thinset products have grown in complexity from the original concept of bonding to porous masonry surfaces. Current installation needs have us bonding to a wide variety of surfaces under numerous circumstances. Hence today’s tile products and installation environments often require a much higher level of performance. There are almost an overwhelming number of specialty thinsets available today tailored to meet a specific need.
How about spreadabilty and coverage? Installers have long been known for watering down thinset and grout to get the consistency they like. Watering down thinset has a dramaticly negative effect on the bonding capabilities. I was recently on a job where the thinset was poured into a pile under the center of each 24” tile which was then nestled flat to the adjoining tile. The result was loose tile and a lot of broken edges.
Another big bonus of some newer thinset mortars is the contact or coverage they provide. It would be hard for most to disagree that coverage is second only to lack of movement accommodation in the most readily identifiable installation issues causing failure. I think most people grossly underestimate the importance that good coverage plays. There are many new “contact” mortars on the market that truly take most of the challenge out of that very elusive and all important uniform coverage. As a contractor, the goal is getting the best possible job done in the least amount of time while dealing with less than ideal conditions whatever they may be. There is almost certainly a product designed for all those conditions worth seeking out.
All this is wonderful; things are good and getting better product wise. BUT, there is a caution. As hard as one may try, there are only so many things you can do with chemistry and engineering. In the end all of these wonderful developments are useless if one does not read and follow the instructions using good work practices. I did not want this to be an article where I harped on getting coverage and using the proper movement accommodation joints. As a contractor, I walked the walk. As an educator, I tried hard to educate using knowledge rather than simply providing instruction on procedures. Now, as an inspector and consultant, I have many opportunities to observe first hand the damages caused by failure to follow instructions and use common sense. We are now in a business where knowledge is as important, if not even more so, than the skills needed to properly install ceramic tile. With the proliferation of tile products and materials used to install them, we are approaching the point of having to be a tile geek to be an effective and profitable installer. Things being slow like they are, now is the time to avail yourself of every possible opportunity to learn more about tile and the products we use to install it. This slowdown will not last forever; there is a lot of work coming our way in the future and it is still true that cream rises to the top.