Ask the Experts – January 2018

QUESTION

I’m having issue with glass tile for one our customers. We’re trying to determine what’s causing the cracking. I believe it might be due to the thinset shrinking. Is it possible that it may be the tile?

ANSWER

Yes, it is possible that the glass cracking could be due to thinset shrinkage as it cures, especially if the maximum bond coat thickness of the thinset was exceeded. But looking at the two photos you sent, here are my guesses.

In the first photo that includes the glass door and hinge, it appears that the glass may potentially have cracked from:

  • over-tightening of the screw through the hinge
  • a minor misalignment of the hole drilled in the glass to accept the screw
  • weight of the door on the fastener at the pressure point if all components of the door installation were not properly aligned or balanced.

In the second photo showing the closeup of the grout joint, it is difficult to know what caused these small fractures. The photo is taken too close to see a context of the location in the shower. It appears that the photo was taken very close to the glass and the fractures are fairly small. My guess is the fractures may have been in the tile at the time it was installed and they weren’t noticed by the installer.

If you need a solid determination of these fractures, a third party consultant that can make an onsite evaluation may be needed.

I hope this helps.

Mark Heinlein – CTI #1112, NTCA Training Director, Technical Trainer / Presenter

QUESTION

We are members of NTCA and would love some technical advice on thin panel installation.

We are supplying large-format, thin porcelain panels for an exterior façade in Oakland, Calif. It is approximately 2,500 sq. ft. at 102˝ x 47˝ x 6.5mm and we are researching installation options for the owner that do not involve the normal setting method.

It would be great to know what options there are for a “rail & clip” system versus full contact installation.

At the very least, it would be great to get some information on the guidelines and practices for installing thin panels using some sort of clip or fastening system.

ANSWER 1

Thanks for contacting us. I took a quick look at the manufacturer’s instructions. They are very typical of most gauged porcelain tile panel manufacturers. I did not see anything other than the direct bond method as an option for installation. Most distributors of thin porcelain tile have been working with installation product manufacturers and tool companies to present a system approach to installation. Some even require the use of manufacturer trained installers.

Last April there were new standards added for this product. ANSI 137.3 and ANSI 108.19.

ANSI 137.3 deal with standards for the product itself. ANSI A108.19 deals with the installation of the product.

I would encourage you to reach out to the manufacturer to see if they would recommend another fastening system. We always encourage our members to follow manufacturers’ instructions explicitly. It decreases your liability in projects.

Robb Roderick, NTCA Trainer/Presenter

ANSWER 2

Thank you for contacting our NTCA Technical Team with your question.

Robb is correct. ANSI A137.3 and ANSI A108.19 are the industry standards adopted this year for the production and installation of gauged porcelain tile and panels/slabs. These standards call for the installation of this material in a thin-bed type system with special emphasis on the installation process for floors and walls outlined in A108.19.

As Robb stated, it is important to follow the tile manufacturer’s instructions. Contact them to be sure you understand their instructions thoroughly. Deviation from installation instructions can result in lack of warranty coverage and/or acceptance of risk by the installation contractor.

The Tile Council of North America (TCNA) has the new standards available on its website for electronic download and it is taking pre-orders for a limited-edition hard copy. You can find the information to purchase an electronic version or reserve your hard copy on the TCNA website www.tcnatile.com/products-and-services/publications/218-english-publications/227-ansi-a137-3-and-a108-19.html or http://bit.ly/2i4iP4p.

Local codes will likely have specific requirements for installing tile above a certain height, especially on an exterior.  Please be certain to contact the code official responsible for the municipality this installation is located in.

Many setting material manufacturers make specialty mortars for installation of these tiles.  You will want to involve your setting material manufacturer to help you determine the best mortar for the application and ask them to work with you to write a site-specific system warranty based on their instructions and industry standards.

I am not aware of any mechanical rain-screen type fastening systems for use with gauged porcelain tile/panels; however, some tool and equipment manufacturers make a clip-type system that is used in conjunction with a thin-bed bond coat installation to provide additional mechanical attachment of large tiles in a vertical installation. One such system is manufactured by Raimondi. For more information about that system please contact Donnelly Distributing/Raimondi USA at 262-820-1212 or [email protected]

Mark Heinlein – CTI #1112, NTCA Training Director and Technical Trainer/Presenter