Ask the Experts – September 2018
Ask the Experts Q&As are culled from member inquiries to NTCA’s Technical Support staff. To become a member and make use of personal, targeted answers from Technical Support staff to your installation questions, contact Jim Olson at [email protected]
I have a client whose installer used mastic to install white marble and now it’s turning yellow.
I looked in the TCNA Handbook, but could not find any information. Can you please guide me where it is mentioned?
ANSI A136.1 is the American National Standard Specification for Organic Adhesives for Installation of Ceramic Tile. It provides information for use of Type 1 and Type 2 organic adhesives for installation of ceramic tile. ANSI A108.4 is the Standard for Installation of Ceramic Tile with Organic Adhesives or Water Cleanable Tile-Setting Epoxy Adhesive.
The 2018 TCNA Handbook contains information about selecting the correct products to install natural stone in these locations:
- The Natural Stone Selection Guide near the front of the book includes a subsection “Considerations When Selecting Installation Materials.”
- The 2018 TCNA Handbook includes approximately 66 methods for installation of natural stone, including movement joint guidelines. To my knowledge, none of the installation methods for natural stone list organic adhesive as a suitable material for the bond coat. Typical bond coats detailed in the “Materials” section of the stone methods are cementitious or epoxy.
The TCNA Handbook’s Setting Materials Selection Guide (page 17 in the 2018 edition) includes a subsection for using “Organic Adhesive” in which it is described as suitable for setting ceramic tile.
As you have already discovered, organic adhesive is not identified as a bond coat for installation of natural stone tile. One of the reasons is the result experienced in the white marble installation that has yellowed.
I have found that some manufacturer’s technical data sheets for their organic adhesives specifically state they are not to be used for setting natural stone. I hope this helps.
– Mark Heinlein, NTCA Training Director, NTCA Technical Trainer