Ask the Experts Q&As are culled from member inquiries to NTCA’s Technical Team. To become a member and make use of personal, targeted answers from NTCA’s Technical Team to your installation questions, contact Jim Olson at [email protected].
QUESTION
I have a question about a Dekton application. When double gluing, it was indicated to use a toothed trowel to apply mortar to the tile. Lately some suppliers and UNE EN 138002 recommend applying mortar with a smooth trowel. What do Tile Council of North America (TCNA) standards say about this?
ANSWER
The American National Standard Specifications for installing Gauged Porcelain Tiles/Panels/Slabs (GPTP/S) such as Cosentino Dekton are found in ANSI A108.19 (Interior installations) and ANSI A108.20 (Exterior installations). These documents provide step by step instructions for installing GPTP/S.
ANSI A108.19 Section 12.0 Application of Bonding Mortar describes the recommended troweling process in detail.
- A108.19 Subsection 12.6 states “Using a notched trowel of type and size recommended by mortar and tile manufacturers, comb mortar onto substrate and tile uniformly with no bare spots.”
- A108.19 Subsection 13.0 lists the additional steps for embedding the tile after troweling.
- A108.19 Subsection 14.0 states the required mortar coverage for properly supporting the tile.
The application of the adhesive bond coat will vary somewhat depending on the adhesive being used and the panel being installed. Typically, the panel manufacturer conducts in-house testing by installing their panels with a variety of adhesives from a variety of setting materials manufacturers. The results of the testing will determine the combination of trowel types and sizes for the substrate and the panel to achieve optimum bond coat coverage for a variety of adhesives.
In addition to the installation standards, methods for installing GPTP/S are published in the TCNA Handbook for Gauged Porcelain Tiles and GPTP/Slabs Installation.
It’s recommended that you purchase both of these documents from the NTCA store:
- ANSI A137.3 / A108.19 / A108.20: https://tinyurl.com/yc5srwme
- TCNA Handbook for Gauged Porcelain Tiles and GPTP/Slabs Installation: http://tinyurl.com/mskzbf24
Electronic versions are available for purchase from the Tile Council of North America at https://tcnatile.com/product-category/publications/
