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 technical.raimondiusa@aol.com

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

Ask the Experts – December 2017

This month’s Ask the Experts focuses on two recent questions concerning installing resin-backed stone.

QUESTION

Can you give me some guidance on working with resin-backed stone?

ANSWER

The issue that we have with resin-backed stone is there is no standardization. The backing could be composed of epoxy, polyester, urethane or a variety of other types of resin.  If there was some consistency to the resin backing, setting materials manufacturers could probably produce thinset that would work. Epoxy adhesives are the safest bet, and should always be used on moisture-sensitive stone.

When installing resin-backed stone, you should contact the stone provider for installation instructions. Many of them are not suitable for installations in wet areas.

The 2017 TCNA Handbook addresses some of this in the Natural Stone selection guide on page 10. The NTCA Reference Manual has a tremendous amount of information about this situation in its mesh-backed stone white paper on page 179. Both will point you toward the use of epoxy adhesives.

Somemanufacturersoftheseresin-backedstoneshaveincorporatedsandandotheraggregatestotheirbackingstohelpwithamechanicalbond,andmakeclaimsthatalatex-modifiedthinsetcanbeused.Iknowpeoplehavescarifiedandorprimedthebackofthesetilesinordertousemodifiedthinset.Withouttheendorsementofthethinsetmanufacturerandthestoneprovider,theseinstallationsarerisky.Iwouldproceedwithcaution.

Robb Roderick, NTCA trainer/presenter

QUESTION

I installed a large resin-backed marble tile on a fireplace wall with a glass-covered fireplace insert that produces a lot of heat, and measured tiled surface temp was about 250+ degrees in direct vicinity of the firebox. I have several issues.

Issue one – We used a polymer-modified thinset to install the tile.  I didn’t realize till after the job was done that it does not stick to resin-backed tile.

Issue two – Upon further research I should have used an epoxy thinset, but from what I was told it is only okay for temps up to 180 degrees.

Issue three – Is the resin on the back of the tile okay to be in contact with that kind of heat?

I am receiving very little help from my tile supplier, I have a very unhappy client, and I am eager to make the fix but I need to know the correct approach so I don’t have a problem again.

Thanks in advance for your help.

ANSWER

There are no industry standards for the resin/resin-mesh backing on stones. The best way to learn what the resin is composed of and what its temperature rating is, is to get the information on it from the manufacturer or stone quarry that put it on the stone, or a lab can examine it. I personally do not have information on the temperature ratings of various resins used on stone backing.

You can reference the NTCA’s Mesh Backed Stone and Tile White Paper (see the Stone section in this issue, page 78 for the paper), which discusses the other issues you described. This information should help give you a better understanding of the application of resin-backed stones in various installations.

It sounds like you will be considering a tear-out and rebuild to ensure that you achieve the proper bond and meet the temperature range of this particular fireplace. I suggest contacting the stone manufacturer/quarry to determine the type of resin, or if that isn’t possible, replace it with a stone that is not resin/resin-mesh backed. I also suggest contacting the manufacturer of the setting materials (i.e. thinset mortar or epoxy and grout) that you will plan to use to set the stone. Many product Technical Data Sheets include this information and can be found on their manufacturer’s websites, or a call to their technical service department will help you determine the correct setting materials to withstand the temperature ranges for this product.

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

TECH TIP TUESDAY: ASK MARK – 11/28/17

Contractor Member Question

Mark,

The photo attached shows a stain in the marble, my client used stone poultice to pull out the stain, then sealed the tile. Everything was fine until she took a shower for the first time, and the stain reappeared. What are your thoughts?

 

 

 

 

 

 

 

 

Mark’s Response

Thank you for contacting the National Tile Contractors Association.
It appears to me the stain (or darkening) may possibly be caused by water pooling beneath the tile in a potential low spot formed in that section of the shower pan.  Do you know if the darkening of the stone lightens with time / as it dries out?  It may or may not be a possibility that the initial removing of the “stain” by application of a poultice may have been coincidental to the stone simply drying out (i.e. from mortar curing under the stone).
I have attached a copy of the NTCA’s Mesh Backed Stone and Tile white paper.  This may shed some more light on the issue with this installation.
Many sealers protect the molecular structure of the tile from staining but do not keep water from passing into the stone and potentially darkening it. To learn more about how sealers work, here is a link to a complete listing of NTCA’s archived webinars.  https://www.tile-assn.com/?page=webinars
Please view the webinars I’ve listed below for more information on how sealers work and other relevant information:
I hope this helps.
Mark Heinlein
Technical Training Director

TECH TIP TUESDAY: ASK MARK – 11/21/17

Contractor Member Question

Mark,

Is there a way to determine what a stain on the surface of a tile is? We run into this problem every once in awhile.  I currently have a job that has been complete for a few months and they have sent pictures claiming the spots are thinset, membrane or grout.  I do not believe they are any of those things. Is there a way to tell? Please advise.

Mark’s Response

A recognized tile consultant either owns, or has access to laboratory technology that can test deposits on the surface of tiles.
A list of NTCA’s recognized consultants can be found on the NTCA website at this link:  http://www.tile-assn.com/?page=recconsultants
Any of the consultants listed on this page should be able to assist you.
I hope this helps.
Mark Heinlein
Technical Training Director

Ask the Experts – November 2017

QUESTION

I want to install porcelain tile in my kitchen and my condo association requires a 1/4” cork underlayment for sound mitigation, but my installer and everyone else I’ve spoken with tells me I shouldn’t use cork in a wet area. One installer told me that the NTCA does not recognize 1/4” cork as a suitable substrate for tile applications. Can you tell me if that’s true and, if so, is there some documentation about this that I can present to my condo association?

ANSWER

In the NTCA Reference Manual, cork is listed as a questionable substrate for tile. There are several other bonded sound-reduction membranes that are designed specifically for tile installations. Bonded sound reduction membranes may be trowel-applied, sheet, or composite membranes that are bonded to a suitable substrate so that tile can be bonded directly to the membrane. Their purpose is to reduce floor impact noise.

Material specifications for these products are contained in ANSI 118.13. I suggest finding a substitute for the cork that meets ANSI 118.13. Take the technical data from that product and present it to your condo association for approval. I hope this helps.

Robb Roderick,
NTCA Technical Trainer/Presenter

QUESTION

Can you please tell me what the tolerance for lippage for 6”x 36” plank tile would be? The builder is quoting 1/8” which they said is the thickness of two quarters. The tile seems good the long way but the short way – walking across in your bare feet – you feel it.

ANSWER

The American National Standard Specification for the Installation of Ceramic Tile (ANSI A108) defines acceptable lippage for Pressed Floor and Porcelain Tile that meets the specifications for ceramic tile (found in ANSI A137.1) for typical installations of tile to be as follows:

  • All sizes of Pressed Floor and Porcelain Tiles with grout joint widths of 1/16” wide to less than 1/4” wide: Allowable lippage is 1/32”.
  • All sizes of Pressed Floor and Porcelain Tiles with grout joint widths of 1/4” wide or greater: Allowable lippage is 1/16”.

For reference: 1/32” is roughly the thickness of a credit card. 1/16” is roughly the thickness of one penny.

The plank tile you describe is very likely a Pressed Floor and Porcelain Tile. The manufacturer of the tile can tell you whether it was manufactured to the specifications in ANSI A137.1 (it is usually printed on the carton).

I would be happy to discuss any questions your builder or tile installation contractor may have about lippage or other installation standards that can have an effect on lippage.

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

QUESTION

Does a shower pan membrane need to be a solid, continuous piece, or is it all right if one corner is completely sliced up and then caulk applied to all cracks? It seems unsafe, and the weight of the concrete and tile could break open all of the cuts. Please help. Thank you very much.

ANSWER

It sounds like you are having a traditional mortar bed type installation constructed that utilizes a waterproofing liner over a pre-sloped pitch.

It is critical to install this, or any type of waterproofing system, in a manner consistent with tile industry methods and standards and manufacturer’s instructions. Rips, tears, cuts, punctures and improperly-sealed seams lead to leaks and failures of the system. With any type of shower installation, I recommend conducting a water test of the system before mortar is placed. In many locales, this is a code requirement placed on the plumbing permit.

The proper methods and details to construct this and many other type of shower pan installations can be found in the TCNA Handbook. If your contractor is a member of the National Tile Contractors Association they will have a copy of this handbook and know how to use it. They should also have a copy of the ANSI A108 standards that provide detailed instructions for the requirements of mud bed installations.

I will be happy to speak to your installation contractor to help them with any questions they may have about this or any other installation. Please feel free to have them contact me. If they are an NTCA member, they are familiar with this service we provide our members. If they are not a member, I would be happy to discuss with them the many benefits of membership including technical support, free training opportunities and obtaining and using the industry standards to base their installations on.

I hope this helps!

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

October 2017: TileLetter – Ask the Experts

QUESTION
I have a floor installation with a relative humidity reading of over 90%. Can you advise me of steps I might take to prevent a failure in this installation?

ANSWER
This is a very high reading and beyond the capabilities of most setting materials. In general, most setting products perform well with readings of 3 lbs/1,000 sq. ft./24 hours in calcium chloride test, or readings less than 75% using a relative humidity test. The effect of moisture on floor covering is a huge problem across the United States. Not addressing this issue with a moisture mitigation system will affect the longevity and performance of this installation and probably lead to some type of failure. Some manufacturers have moisture mitigation systems that include waterproofing membrane, and specific thinset mortars that are warrantable up to 12 lbs/1,000 sq. ft. and above 90% relative humidity. My advice to you is to use a moisture mitigation system and the appropriate setting materials that can handle that level of moisture.

There are thousands of setting products that are affected by differing amounts of moisture in a variety of ways. Using the information you have received from a relative humidity test in concert with technical data from your setting material provider is paramount for a successful installation.
– Robb Roderick,
NTCA technical trainer/presenter

 

QUESTION
I was helping a friend with a concrete shower base install and ran into a problem. We poured the concrete base with the required portland cement/sand mixture at the correct slope. About a month after the tile install, the grout started chipping out. After regrouting it continued to fall apart. We pulled up the tile and it came up pretty easy. It’s been about five days now and the concrete still looks wet. I cleared out the area around the drain to make sure the weep holes were clear and they were. Why is the base still wet? I’m hesitant to install new tile on top until it’s dry. Help please!

ANSWER
Can you tell me if a pre-slope of a 1/4” per 12” was installed first then a liner placed over the preslope and sealed to the clamping ring drain, then the mud pack over that? Or, was a surface-applied waterproofing membrane installed on top of the sloped dry pack mud bed and sealed via the divot method to the clamping ring drain? If not, the mud pan is going to hold water if there is no membrane channeling it to the drain system.

Showers and pans are complex systems that must be installed properly to protect the rest of the structure they are installed in. I strongly suggest hiring a qualified professional to perform this installation. The NTCA is the world’s largest association of tile contractors. You can locate an NTCA Member contractor and a Certified Tile Installer in your area by visiting the following sites: www.tile-assn.com or www.ceramictilefoundation.org.

– Mark Heinlein,
NTCA technical trainer/presenter

RESPONSE

Thanks for the quick reply. It looks like I did all of the correct things outlined in your email with exception of the divot method. Now after reading up on the divot method I have questions. Does it require a drastic slope to the drain as shown in the picture below? Also does this method call for a paint-on membrane to be put on the very top? Let me know and thanks again for your time.

ANSWER

Either a liner on the pre-slope or a surface-applied membrane must be used. Not both. Whichever one is used, it must be properly sealed to the clamping ring drain. The divot allows for using a surface-applied membrane in lieu of a pre-slope and a liner with a clamping-ring drain system. Or, a bonding-flange drain system can be utilized to accommodate a surface-applied membrane.

There are many variables, techniques, best practices and standards that must be considered, applied and performed correctly in every tile installation. Showers and wet areas are especially critical. I suggest contacting a qualified, certified, knowledgeable, experienced professional using the links I sent previously. – M.H.

RESPONSE

Mark, thank you. I did the liner on the pre-slope so I should be okay. I just wasn’t sure why the base retained so much moisture even with the liner, slope, and weep holes all in working order.

ANSWER

Drainage issues could potentially be related to the site mix/recipe or consistency of the mix, method of application, etc. Perhaps the problem with the grout could be related to the type and mixing and application of grout or the type and mixing of the mortar and troweling technique used to bond the tile to the mud pack. – M.H.

 

Tech Tip Tuesday: Q & A With NTCA Training Director Mark Heinlein – 10/31/2017

Consumer Question:

Hello! I’m trying to find out if there is an industry standard for the conversion rate of m to kg for Porcelain tiles based on thickness and if so, where I would be able to find this information. Thank you in advance for your assistance.

Mark’s Response:

Thank you for contacting the National Tile Contractors Association.

The Tile Council of North America (TCNA) Handbook for Ceramic, Glass and Stone Tile Installation contains an Appendix (B) discussing “Estimated Weights for Floor Installations.”

This appendix provides a discussion of assumptions for dead load weights of ceramic and stone tile and related setting materials. The assumptions are given in terms of imperial / US Customary (pounds per square foot) measurement vice metric (kilograms per square meters).  Several tables giving the weight calculations for methods included in the handbook are provided in Appendix B.

If you do not own the TCNA Handbook, a copy can be purchased from the NTCA’s Online Store under the Industry Technical Manuals section at this link:  https://tile-assn.site-ym.com/store/default.aspx?

I hope this helps.

 

Mark Heinlein

NTCA Training Director

Tech Tip Tuesday: Q & A With NTCA Training Director Mark Heinlein – 10/24/2017

Member Question:

We are encountering issues with a wall tile installation. I am trying to find out what the wall assembly should consist of in regards to metal studs, horizontal reinforcement, etc.   Your response would be greatly appreciated.

Mark’s Response:

Thank you for contacting the National Tile Contractors Association.

Please refer to the Tile Council of North America (TCNA) Handbook Method W243-17 for the details and best practices for the wall installation you are dealing with.  This method requires metal studs to be well braced; 20 gauge (0.033”) or heavier; minimum depth 3-5/8” for commercial applications.  The gypsum board must meet ASTM C1396/C1396M with a minimum of 1/2” thickness for single layer applications and must be installed per GA-216.  Maximum allowable variation of the substrate (for the installation of 12”x12” tile) is to not exceed 1/4” in 10’ (feet) from the required plane with no more than 1/16” variation in 12” when measured from the high points in the surface.  Additionally, details for movement and expansion must be met as required by TCNA Handbook method EJ-171.

I have attached a photo of the section of the 2017 TCNA Handbook that discusses “Equivalent Gauge” Steel Framing in case that material has been used on this project.

In addition, the NTCA Reference Manual includes an excellent discussion of EQ Gauge steel framing.  It states, in part, that the wall framing should meet a deflection limit of L/360 for the rated load based on the properties of the stud alone.  It further states that it is the responsibility of the design professional and framing contractor to ensure that wall assemblies for tile and stone finishes are designed and assembled to meet performance requirements, and all manufacturers of EQ studs will have the technical data needed for design and confirmation of performance requirements.

I am glad to learn you will be joining the NTCA.  As a member, you will find many benefits including tremendous networking and educational opportunities with many likeminded tile industry professionals looking to improve their level of performance and education based on tile industry standards. Other benefits include receiving a copy of the TCNA Handbook and the NTCA Reference Manual each year with your membership renewal.  I look forward to discussing membership with you next week when you call back.  In the meantime, please visit www.tile-assn.com for more information.  You can view additional member benefits at this link:  http://www.tile-assn.com/?page=Membership  you can also join by clicking on the “Join Now” link found anywhere on our website.

I hope this helps!

Mark Heinlein

NTCA Training Director

Tech Tip Tuesday: Q & A With NTCA Training Director Mark Heinlein

Member Question:

I have a job where we installed a porcelain tile. It is 8” x 15” and the side walls are fine but the wet walls are not good.  The worst part is they have that system of lighting where it is shining down directly from above so it shows all discrepancies and shadows. Is there anything in the industry standards that allows for a tolerance for a little lippage?

Mark’s Response:

Thank you for contacting the National Tile Contractors Association.

The standard for lippage is found in ANSI A108.02 Section 4 (copy attached) and is echoed in the TCNA Handbook.  Generally speaking, 1/32” in addition to the allowable warpage of a tile manufactured in accordance with ANSI A137.1 is the allowable lippage for wall mount mosaics with a grout joint width of 1/16 – 1/8”.

I understand these strip mosaics can be difficult and time consuming to install.  You are correct that substrate flatness is the place to start to help ensure the installed lippage is within tolerance.

The NTCA Reference Manual has an excellent section describing Wash Wall Lighting and how to avoid problems that can be associated with it.  If you have your Reference Manual at hand, it will provide some good reading on this topic.

The 2017 TCNA Handbook contains a section on Visual Inspection of Finished Tilework.  I don’t have my book close at hand but it is in the first 30-40 pages.  It may help your situation that visual inspection of wall installations is performed at 36” from the tilework.  Please take a look at that section in the Handbook and see if it can work for you in this case.

Please let me know if I can help with any further questions you might have after you are able to review the documents I listed above.

I hope this helps!

Mark Heinlein

NTCA Training Director

Tech Tip Tuesday: Q & A With NTCA Training Director Mark Heinlein

Member Question:

Is there a reference in the NTCA Reference Manual or other publication pertaining to use of waste or fall off that is standard in tile installation?

Mark’s Response:

Thank you for contacting the National Tile Contractors Association.

I am not aware of a written recommendation for calculating waste percentages for tile estimates.

My recommendation is:

  • Straight lay / Basic installations:  5% + sufficient attic stock
  • Diagonal / Slightly more complex installations:  8 – 10% + sufficient attic stock
  • Complex designs or patterns:  12 – 15% + sufficient attic stock

The size of the installation will make a difference.  Very large, well planned areas may not generate much waste.

Installations involving hallways and many adjoining rooms may require calculating additional waste.

Careful review of the plans, designs and details is necessary for each job.

I hope this helps.

Mark Heinlein

NTCA Training Director

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