The Tile Council of North America (TCNA) Handbook, the Industry's Guide for Installation Practices, now in its 49thedition, has been the vehicle guiding proper tile installation for many years. Architects, specifiers and other design professionals utilize it, along with the ANSI (American National Standards Institute) Specifications, as a basis for the methods they want the tile mechanic to follow when installing tile on a project.  Unfortunately, many people associated with the tile industry are not familiar with the Handbook. The purpose of this article is to overcome a portion of this great unknown and will focus on just under 13% of the information available.
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The 2012 edition of the Handbook is the culmination of the efforts of many talented and knowledgeable people in the tile industry.

The 2012 edition of the Handbook is the culmination of the efforts of many talented and knowledgeable people in the tile industry. The committee, which presently includes 37 members, meets every two years (on even-numbered years) to decide by majority vote which of the newly presented methods will be included in the upcoming edition. The committee also reviews and modifies existing methods that reflect new product innovations and/or updated installation methods.

During the extensive overhaul of the 2011 edition, it was decided to gather a broad list of pertinent installation-related information, and for the first time in the Handbook's history, put it in one place for quick reference. The first 38 pages (13%) are broken down into several categories, including: Product Selection Guide, Field and Installation Requirements, Floor Tiling Installation Guide, Environmental Classification and Using the TCNA Handbook for Specification Writing. Due to the limited space allotted to this article, we will look at just a few of the listings.

The Product Selection Guide includes the five Ceramic Tile Types, shown in Text #1, and details the characteristics of each group.

Text #1:

Ceramic Tile Types

Ceramic tiles suitable for TCNA Handbookinstallation methods are those that meet the specifications outlined in ANSI A137.1 American National Standard Specifications for Ceramic Tile. ANSI A137.1 contains performance and aesthetic criteria for the five major types of ceramic tiles: porcelain, pressed floor, mosaic, quarry and glazed wall tiles.

Porcelain tiles are ceramic tiles for floor and wall applications with a water absorption of 0.5% or less per ASTM C373 test method and that are generally made by the pressed and extruded method. This category does not include materials with very little or no crystallinity, such as glass tiles. Tiles specifically warranted as porcelain by a manufacturer, and independently tested and confirmed to comply with this water absorption requirement, may be certified by the Porcelain Tile Certification Agency (PTCA).

Pressed floor tiles are ceramic tiles made by pressing, having a facial area equal to or greater than 9 square inches, and although specified by manufacturers as appropriate for floors, are also suitable for use on walls.

Ceramic mosaic tiles are tiles for floor and wall applications having a facial area less than 9 square inches, which are typically mounted on sheets or strips.

Quarry tiles are ceramic tiles for floor and wall applications made by the extrusion process from natural clay or shale.

Glazed wall tiles are nonvitreous ceramic tiles intended for interior use, and are not required nor expected to withstand excessive impact or exposure to freeze/thaw cycling. Tiles in this category are not intended for use on floors.

The Aesthetic Classifications of tile appearance provides the manufacturer with a method to describe the uniqueness of each group, shown in Text #2, to the end user during the selection process.

Text #2:

Aesthetic Classifications

Tiles may vary in color, texture or appearance according to the manufacturer's design for that particular tile series or product line. The following designations classify the range of such variation.

V0 tiles ties are very uniform in appearance and smooth in texture. When measured by a colorimetric spectrophotometer, they have an overall color difference (delta E) of less than 3 Judds.

V1 tiles have a generally uniform appearance with minimal production run differences among pieces. Some color differences can be observed.

V2 tiles are similarly colored with variations in texture and/or pattern, which are clearly distinguishable.

V3 tiles are moderately variant, and although the colors and/or textures present on a single piece are indicative of the colors and/or textures on another, the amount of colors and/or textures on each piece may vary significantly. It is recommended that the range be viewed before selection and that a mock layout be made.

V4 tiles are substantially variant with random color and/or texture differences from tile to tile, where one tile may have totally different colors and/or textures from another. Because a final installation with V4 tiles will be unique, it is recommended that the range be viewed before selection and that a mock layout be made.

Although checking the range of color and texture for V3 and V4 tiles is specifically recommended, all of the categories above have some range and should be checked and generally installed from several boxes in random fashion to avoid aesthetic issues.

Due to the increased popularity and use of glass tile, it is imperative that the installer and end user know what to expect both in the characteristics and performance of the product selected. The newly approved ANSI A137.2 for glass tile now establishes a "standard" to which the tested tile is judged. In Text #3, these details are explained and will equip the consumer with the tools necessary to make an educated decision.

Text #3

Glass Tile Types

Based on temperature of formation, there are three types of glass tile: cast glass tile, fused glass tile and low-temperature-coated glass tile. Each type can be subdivided, based on size, into three subcategories: large format glass tile (typically larger than or equal to 3" x 3"), mosaic glass tile (typically larger than 3/4" x 3/4" and smaller than 3" x 3") and miniature mosaic glass tile (typically smaller than or equal to 3/4" x 3/4"). Cast, fused, and low-temperature-coated glass tiles are produced in many sizes with wide varieties of opacity ranging from opaque to translucent. All glass tiles have characteristics different from ceramic tiles.

Cast glass tiles are formed in a liquid state at 1600°F or higher. Many cast glass tile surfaces are wavy and slightly textured with inherent folds, bubbles, and creases. These unique intrinsic properties are achieved through the casting process.

Fused glass tiles are typically made from sheet glass units that are altered through heat between 1023°F and 1599°F. During manufacturing, different materials and glazes are fused to the sheet glass units, usually in multiple stages, to create a variety of colors and patterns. Fused glass tile surfaces can be smooth, textured, uniform, or nonuniform.

Low-temperature-coated glass tiles are made from sheet glass units that are altered at temperatures less than 1022°F. Typically, these alterations involve heat-transferred coatings applied to the back of transparent sheet glass units. These coatings can contain wide varieties of colors and patterns.

Installation and Performance

Although many TCNA Handbookinstallation methods can be applicable to glass tile installations, when using these methods with glass tile, it is necessary to consider the aesthetic and performance aspects of the tiles being used. Consult tile manufacturer for any proprietary installation guidelines and relevant physical properties for the application being considered.

Impact and Abrasion Resistance: Generally, glass tile is less resistant to abrasion and impact than ceramic tile: select glass tile suitable for expected traffic.

Thermal Shock Resistance: Glass tile is more sensitive than ceramic tile to thermal shock, and manufacturers should be consulted regarding the performance of glass tile products for installations where rapid temperature changes are expected, such as some exterior installations, kitchen countertops, and fireplace surrounds.

Thermal Expansion: Because glass tile expands more than ceramic tile, more movement accommodation is necessary. Proper movement joint placement is essential for the performance of glass tile installations. Also consult manufacturer for minimum distance of the tile from direct heat sources (fireplaces, stoves, etc.).

Limited Flexibility: Although glass tiles often have breaking strength values as high or higher than ceramic tiles, they require a more rigid substrate.

Bonding to Membranes: Bonding translucent glass tiles directly to membranes or other impervious surfaces can result in visible moisture behind the tile. When used, membranes should be placed behind or below the tile substrate. If a membrane is used on the face of the substrate, select only opaque glass tiles.

Submerged Environments:  Consult manufacturer for use of glass tile in submerged installations, such as swimming pools and fountains. Some tiles, especially back-mounted mosaics with re-emulsified glues and/or insufficient contact area between the tile backing and mortar, may delaminate in submerged applications. Follow manufacturer recommendations regarding submerged applications and exposure to pool or fountain chemicals if applicable.

Substrates: Although the types of substrates recommended for glass tile installations are similar to ceramic tile installations, extra attention should be given to substrate stability, rigidity, and preparation. Where a substrate is appropriate, glass tile will be listed as an option in the Materials section of the applicable method.

Substrates should be sufficiently flat to allow uniform coverage and avoid excessive mortar thickness. Glass tile should not be installed on single-float mortar bed walls framed with wood or metal; and glass tile should never be bonded directly to wood substrates. For above-ground slabs, reinforced mortar beds may be required, especially for large-format glass tile. Some manufacturers require mortar bed substrates be cured a minimum of 7 days prior to glass tile installation.

The Substrate Requirements category is loaded with information that is essential for proper tile installation. An often misunderstood requirement for installing natural stone tile over wood substrates clearly states the structure requirement in Text #4 and in detail F250-12 STONE shown on pages 227 and 228 of the 2012 edition.

Text #4:

Natural Stone Tile Installations Over Wood Substrates

Two layers of structural wood panels are required on floors to receive stone tile when backer board will be used as the tile substrate. The MIA prohibits installation of stone tile over single-layer wood floor systems under backer board because of the discontinuity of the system at seams between the subfloor panels. If an unbonded mortar bed will be installed as the tile substrate, a single layer of wood subflooring is permitted. Strongbacks, bridging, or other load-sharing members maybe required within a wood framed system to reduce differential deflection between adjacent framing members; project design professional is responsible for determining the necessity of such.

In both ceramic tile and natural stone tile installation, trouble-free and long-lasting performance demands adequate mortar coverage. Text #5 provides these minimum requirements.

Text #5

MORTAR AND MORTAR COVERAGE

Mortar Coverage for Ceramic Tile: Average contact for dry areas is 80% and for wet areas is 95%. Mortar coverage is to be evenly distributed to support edges and corners.

Mortar Coverage for Natural Stone Tile: Mortar coverage must be sufficient to prevent cracks in the stone resulting from voids in the setting bed. In dry and wet areas, the minimum coverage is 95% with no voids exceeding 2 square inches and no voids within 2" of tile corners. All corners and edges of the stone tiles must be fully supported, and back-parging, or back-buttering, is recommended in all areas. Coating the back of the tile, however, does not constitute coverage, which is the area where the mortar makes contact with the tile and the substrate.

Two additional extremely important factors in the tile installation process, shown in Text #6, show how thin-bed mortars are to be applied as well as a caution on the thickness of the mortar used to bed the tile.

Text #6:

Directional Troweling: To ensure proper coverage of the bonding surface of 8" x 8" and larger tiles and to provide full support of the edges and corners, select a notched trowel sized to facilitate the proper coverage. Key the mortar into the substrate with the flat side of the trowel. Comb with the notched side of the trowel in one direction. Firmly press tiles into the mortar and move them perpendicularly across the ridges forward and back to flatten the ridges and fill the valleys. This method can produce maximum coverage, with the corners and edges fully supported, without back-buttering or beat-in. Periodically remove and check a tile to ensure proper coverage is being attained.

Excessive or Nonuniform Depth of Mortar

Many stone varieties, particularly the softer marbles, limestones, and travertines, are extremely vulnerable to nonuniform shrinkage of cement mortar. Uneven mortar shrinkage during curing can produce a fine but visible crack in the stone. This is also true for larger glass tiles. To avoid this, the mortar must be applied in uniform thickness, and within the minimum and maximum thickness allowed by the manufacturer. Substrate preparation, or flattening, is required if the substrate does not meet the substrate tolerances. Mortar bed and self-leveling methods may be a good choice when larger glass tiles or such stones have been selected.

The Handbook information shown here is a fraction of the material presented in this section of the book. If this is the first time you have viewed the TCNA Handbook, I would encourage you to get your own personal copy by going to http://www.tcnatile.com  or call 864-646-8453. Having it in hand will allow you to become better versed in not only knowing the proper installation methods, but also putting the vital information in the first 13% of the book at your fingertips.