November 2019 President's Letter
Thursday, October 10, 2019
Posted by: Trish Moss
Movement joints – why you need them
People who succeed in any profession take pride in their work. As I spent more time in the industry and began to be awarded more challenging installations, our teams took great pride and produced what we thought was often – not always – just about perfect. Looking back, some of them – in fact – were perfectly wrong!
Now, this goes back almost 30 years. I have continued to learn and hopefully know more than I did then. But it’s humbling to look back and realize how much we had to learn. Like the old saying goes, “We don’t know what we don’t know.”
There should never be a time that you stop learning. In hindsight, even though I had been in the industry for several years, I had only a basic understanding of control joints: where to use them, and why and how they need to be an integral part of a tile assembly. Lack of movement joints is one of the most prevalent reasons for tile installation failures.
I used to think I was achieving peak performance by producing cuts with micrometer inside corners or perimeter joints. Little did I know that by making those cuts so tight, I may have been eliminating the installation’s ability to accommodate even minor changes in humidity, temperature or deflection when the installations needed to expand and contract. Just the same – they were cuts produced by a highly skilled craftsman. Too bad they were technically wrong.
Besides just not knowing any better, expansion and perimeter joints are often ignored because they can be a visual distraction. It is difficult to argue with someone who is dead-set against them for aesthetic reasons, because aesthetically, I agree with them much of the time. But, aesthetics don’t trump physics. People usually come to an enlightened understanding of the need for movement joints after an installation has failed.
This is an avoidable and expensive conversation, one you should have only once, or better – never. Once you have had it you will be able to authoritatively instruct someone of the need for properly designed control joints in the installation, especially after having repaired or replaced a failed installation because you did not include them.
Some time ago, I insisted on 5/16” control joints on a 130-foot-long, suspended walkway with a tile floor and full-height tiled wall, with the other wall and ceiling glass, in a windy freeze/thaw environment. They agreed to the joints only after I said that I could not perform the installation without them. More importantly, I had something to back me up, so they didn’t have to take my word for it. I was prepared with the TCNA EJ-171 TCNA Handbook recommendations.
This was several years ago. The control joint standard is even better today, in part because of NTCA members like Kevin Fox of Fox Ceramic in St. Marys, Kan. Kevin recognized that knowledge of the control joint requirements could help avoid potential problems with demanding installations. Kevin did the deep dive into the math and science covering expansion joints. In doing so, he found the need for improvements. As Chairman of the NTCA Methods and Standards Committee he helped make the standard better. EJ-171 is improved today because of Kevin and folks like him whose work benefits the industry. He saw that some of the information needed to be updated and improved it. In doing so, he made it better to protect the consumer and the installation contractor.
There are many products today to help the craftsperson find ways to address movement joints. It feels like there is a much better understanding today of the necessity for them, and less resistance in the design community once the need is explained. We hope you find something to take away in this issue of TileLetter that helps you manage the conversation and installation of movement joints for the benefit of all of your installations.