While all of this was going on, a couple of men in Ohio were changing our industry at that very moment. Paul Dinkel, a tile contractor with a vision, was determined to find a solution to the problem of ceramic tile failures when it was installed over sheetrock. He began experimenting with a glass mesh mortar unit, consisting of a lightweight concrete core covered on each side with a special fiberglass mesh. It would become known as Wonderboard. Together, with his partner Ted Clear, they revolutionized the tile industry with this product. Today, a wide range of products has been developed since Wonderboard's inception, and we refer to them today as backerboards.
Currently, there are five specific types of backerboards recognized by the Tile Council of North America Handbook for the Installation of Ceramic Tile. This includes several new methods recently introduced in the 2005 version of the Handbook. Contractors and sales professionals are constantly asking us our opinion on what type of backerboard to use in certain situations. Our response is understandably guarded. Each one of these products, when installed according to their specific instructions, generally will perform extremely well. It is vitally important that you study the limitations and recommended uses for each of these products.
It is also important to outline this note taken from the TCA Handbook under the definitions of Backer Board types: "The Handbook Conference acknowledged other backer units that are on the market for use as a backing and underlayment with ceramic tile. However, the conferees felt there was insufficient experience and test data available to consider specific comment as to their use. Follow manufacturer's recommendations."
This is important because often there are products out there being marketed and installed that are not currently recognized by this committee. This does not mean they will not work; only that our caution is that you request written guarantees and instructions to use a product of this nature.
Backerboards are used for both floor and wall installations, and represent a large percentage of the total ceramic tile market in relation to substrate use. It is important that the types of backerboards currently recognized in our industry are defined and understood. Even today, there is much misinformation being shared in the field in relation to these products characteristics and performance.
A great example of this relates to the general recommendation by most backerboard manufacturers that you use either a dry-set or latex-Portland cement mortar to bond the product to the subfloor. For years this was explained by many in the industry as a superior way to bond the board to the subfloor, creating a more rigid surface for tile. In truth, the reason for this recommendation is that the mortar assists in providing a leveling bed to the surface, allowing for the installation to meet specified subsurface tolerances requirements of 1/4-inch in ten feet and 1/16-inch in one foot to meet American National Standards specifications.
Additionally, we often are asked if applying mortar to the subfloor prior to installing the backerboard is a requirement. The answer is complicated, because the TCNA Handbook details this practice in all approved methods, but if the manufacturers state in their literature or instructions that it is okay to eliminate this step in the installation you will have to determine how to proceed. This is the type of situation where I would suggest you require written installation instructions for this product.
In an attempt to shed some light on what types of backerboards are currently recognized in the TCNA Handbook, and what products fit into these categories, the NTCA published a document in its Reference Manual Problem Solving Guide. This document was published in 2005 with the intent of assisting industry professionals in the dissemination of the marketing literature being offered to the trade. It is not the intention of NTCA to determine what product fits into each category. This is the responsibility of the manufacturer. However, understanding the specific types is important in order to make decisions regarding what products to use in different installations.