In my more than twenty years in the substrate patching and leveling business, one of my primary objectives has been to educate installers on the proper preparation of substrates. Something emerged recently that has caused me to have serious concerns.  Some individuals representing manufacturers of patching and leveling compounds touting that their products can be installed with “no” prep required.

In part one (FCI, May 2007 issue), we discussed the types of joints and cracks that are placed into, or that develop in, concrete slabs. In this installment, we will look more closely at these joints and cracks from the standpoint of tile installation and make a clear distinction between those that can be addressed by simple installation practices - “the art” - and those that require “science” - the technology represented by the crack bridging/isolation systems that are currently available.

In order to properly address the subject of cracking in ceramic tile installations, it is first necessary to understand where the cracks come from. In this first of a three-part article, we will explore the nature of cracking as it relates to concrete slabs. Understanding how they develop will allow us to understand how best to address them in preventing their effect on our tile installations.

In preparing concrete subfloors to receive new floor covering materials, all good mechanics know how to flash patch and skim coat areas to provide the flat, smooth surface required to install the new flooring. However, when it comes to the variety of construction joints and cracks in the subfloor, there are a number of decisions to be made as to which ones can be successfully filled and which must never be patched.

Having spent the last five plus years immersed in the subject of moisture problems in concrete and how to best control them, I have had the privilege of learning from and sharing information with the most esteemed experts on this subject in both the concrete and flooring industries. In recapping the information gleaned from the wealth of resources available, it became very clear to me that the picture of the problems and how best to solve them is blurred - fuzzy at best.