Technical Focus: Gauged Porcelain Tile, Changes in Industry Standards and the Building Code
As Gauged Porcelain Tile (GPT) continues to grow in popularity, so does the number of changes to our industry standards and even the building code. When GPT first arrived in the U.S. from Europe in early 2010, the industry and installers were suspicious — “How can it be that much larger and thinner, too?” In 2014, the industry released the “Position Statement on Thin Porcelain Tile,” written by the National Tile Contractors Association and tile setters unions. This document stressed the importance of the tile contractor being cautious, as no industry standards were available to establish quality materials and installation techniques and stressed following the manufacturer’s direction. At the time, I was working as a product manager for a tile manufacturer and in the process of creating a GPT, or what we called thin tile, product line. That seems so long ago, but here in 2020, we have ANSI product and interior installation standards that have been out for three years. The future looks positive for GPT as an exterior standard is nearing an ANSI vote and the International Building Code (IBC) will change in 2021 to include larger sizes of all porcelain tile on an exterior.
Sometimes, creating a new ANSI standard can be quite difficult, and many take years, even decades. The creation of the initial GPT installation standard started in September of 2015. A small group of industry consultants, union and trade association representatives, manufacturers of GPT tile and setting materials manufacturers spent several days at Crossville Inc. in Tennessee, installing and observing different techniques and the results of the work. We removed the installed GPT panels the following day to confirm the coverage of the mortar; what difference did the different trowels make, different embedding procedures and what was repeatable? From these results, the ANSI A108.19 installation standard was developed. My understanding is that the tile technical committee started drafting the product standard about the same time. Through hard work, many conference calls and a couple of face-to-face meetings, approximately 18 months later, the ANSI installation and product standards were sent to the ANSI A108 committee and passed. This expedited timeline was unprecedented and accomplished due to the importance of the ANSI standards for GPT.
Soon, the Tile Council of North America (TCNA) published a separate ANSI document with both standards: ANSI A137.3 American National Standard Specifications for Gauged Porcelain Tiles and Gauged Porcelain Tile Panels/Slabs and ANSI A108.19 Interior Installation of Gauged Porcelain Tiles and Gauged Porcelain Tile Panels/Slabs by the Thin-Bed Method. You may wonder why the names, “Gauged Porcelain Tiles” and “Gauged Porcelain Tile Panels/Slabs?” “Gauged” because, at this time, we were addressing thin tiles from 3.5 to 6.5mm in thickness. Today, many manufacturers of GPT also have thick tile from 2cm or 20mm (3/4 inch) to 3cm or 30mm (>1 inch) thickness. The TCNA is just beginning the conversation that there is interest in creating a product standard for these thick porcelain tiles. So, like wire, gauged more accurately describes the thickness. “Gauged Porcelain Tile” refers to GPT less than 1 meter (39 inches) in size, while “Gauged Porcelain Tile Panels/Slabs” measure 1 meter and larger. Why “panels/slabs?” ANSI standards are adopted by a consensus process; some tile manufacturers wanted panels, other manufacturers wanted slabs. Using the consensus process, they agreed to refer to it as “Panels/Slabs.”
Since the original publication, there have been some minor revisions to the ANSI A108.19 interior installation’s standard by three different ballots. One updated a variety of parts of the installation standard, but primarily updated the language in the section 10.2 Installer Qualification Programs language. The second ballot updated information on protecting the installation. There were three appendix items added; one for a graphic visual of the 1/8 inch in 10 feet flatness tolerance and the second added a great graphic of the proper embedding of GPT on floors. The third ballot added Appendix 3, which describes the requirements for the proper format for a GPT installation training program to qualify for a GPT Installer Qualification Program, as listed in the ANSI A108.19 standard.
What is next for GPT? Shortly after the installation standard for interiors passed, a committee was formed to begin work on the exterior installation standard. This has taken a few years, but remains very active and important to the ANSI A108 committee. I would expect an ANSI A108 committee vote on the proposed “ANSI A108.20 American National Standard Specifications for Exterior Installation of Vertical and Overhead Gauged Porcelain Tiles and Gauged Porcelain Tile Panels/Slabs by the Thin-Bed Method Bonded with Modified Dry-Set Cement Mortar or Improved Modified Dry-Set Cement Mortar 2020” standard in the upcoming months. It will address exterior vertical installations.
One of the issues tile contractors have faced with exterior installation of GPT was the limitation on porcelain tile in the IBC 2018, Chapter 14, 1405.10.2 Exterior Adhered Masonry Veneer - porcelain tile, which reads, “Adhered units shall not exceed 5/8 inch (15.8 mm) thickness and 24 inches (610 mm) in any face dimension nor more than 3 square feet (0.28 m2) in total face area and shall not weigh more than 9 pounds psf (0.43 kN/m2). Porcelain tile shall be adhered to an approved backing system.” This language was not entered into the code because of GPT, it was regarding regular 3/8-inch (10-mm) porcelain tile. While GPT was well under the weight limit, GPT seldom comes in sizes <3 square feet in facial dimensions. Bill Griese with TCNA put a small committee together to address the recommended building code change. The committee included Ryan Marino, also with TCNA; Noah Chitty from Crossville, representing tile manufacturing; Brian Trimble from International Masonry Institute (IMI), representing labor; and myself, who represented setting material manufacturers. We were scheduled to present a proposed code change on the size and weight of porcelain tile, including GPT, at the 2019 Code Development: Group B 2019 Committee Action Hearing in Albuquerque, NM. A lot of planning went into this proposal before the August meeting. This small group worked on this with the TCNA and attended the meeting in Albuquerque on May 5, 2019, to present the new building code change proposal. The new proposal was based on larger tiles being the norm today, while being installed with improved mortars compared to when the original language went in the building code 20 plus years ago. We received a unanimous 14-0 committee vote for approval. Just recently, on April 8, 2020, the Final Action Results on the 2019 Proposed Changes to the Proposed Changes to the International Codes for Group B were finalized and released. Our proposal FS1-19 was accepted, as submitted. Many at the code hearing, which is composed a group of building officials, architects and builders, felt it was a needed modernization of the building code for adhered porcelain tile exterior. The new language proposed, which will be printed in the 2021 IBC Chapter 14, 1404.10.2, read, “Exterior adhered masonry veneers-porcelain tile. Adhered units weighing more than 3.5 pounds (traditional porcelain tile, 3/8 inches) per square foot shall not exceed 48 inches in any face dimension not more than 9 square feet in total face area. Adhered units weighing less than or equal to 3.5 pounds (GPT) per square foot shall not exceed 72 inches in any face dimension not more than 17.5 square feet in total face area. Porcelain tile shall be adhered to an approved backing system.” So, traditional porcelain tile can now be installed even larger than 2 x 4 feet with a total facial dimension of up to 9 square feet — three times the previous size of no more than 3 square feet in total facial dimension. For tile weighing 3.5 pounds or less per square foot GPT, they can be up to 17.5 square feet in total facial dimension with no edge exceeding 6 feet.
When this code change goes into effect in 2021, we should have an ANSI exterior GPT installation standard to complement it. This will be a tremendous benefit to our industry and hopefully validate all the hard work that went into getting this building code change passed.
With guidance from a tile manufacturer and the TCNA, we have proposed GPT methods for the TCNA Handbook. It was started off trying to add GPT to existing methods, and after working through a dozen methods, we realized this was a challenging route to go because it is difficult to include notes specific to GPT and small glass tile at the same time. With the TCNA’s help and labor’s involvement, we brought two methods to the TCNA Handbook committee meeting last October at Total Solutions Plus in Nashville, TN. We agreed that those two GPT methods and notes agreed upon would be incorporated into more TCNA methods. I think originally, we submitted 16 methods. The TCNA is currently making changes to those methods. If the committee can agree on more methods, the notes and bullets specific to GPT, then many more methods can be added. The goal would be to have a publication for GPT that would include TCNA Handbook methods and the ANSI standards for the product, installation standards for interior and exterior, all specific to GPT.
There are many more developments for GPT in every aspect of our trade. Setting material manufacturers are launching better wall preparation products that are ideal for large-format tiles and GPT on walls. There are setting materials designed to complement GPT installations with their characteristics like extended open time, non-sag and large and heavy tile mortars. Several of us have launched advanced adhesive technology for the installation of GPT on interior walls. Tool manufacturers continue to release lighter, stronger and more practical tools for the installation of GPT. Weekly, I see new tile manufacturers getting into GPT with amazing colors, styles and stunning visuals. This technology is here to stay, as one large slab or panel of GPT can yield a myriad of sizes and shapes cut from it. This GPT manufacturing technology uses less raw materials, less energy to kiln fire them, and because they are thinner, more can be shipped. If you have interest in learning more about the installation of GPT, get the installation standards and reach out to tile and setting material companies for training specific to GPT. My company did more than 80 GPT trainings last year in the U.S. in multiple facilities and for many manufacturers. If you have been sitting back and waiting for this trend to die, settle in; you will have a long wait.