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

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

TECH TIP TUESDAY: Q & A WITH NTCA TRAINING DIRECTOR MARK HEINLEIN

Question:

Do you have any guidelines on how to install porcelain tile according to ANSI Guidelines you could send me, please?

Mark’s Reply:

Thank you for contacting the National Tile Contractors Association.

Below, I have listed for you the primary tile industry standards, methods and guidelines for the installation of porcelain tile.

  • American National Standards Institute (ANSI) A108 and A118 – American National Specification for the Installation of Ceramic Tile – Material and Installation Standards
  • ANSI A137.1 – American National Standard Specifications for Ceramic Tile
  • Tile Council of North America (TCNA) Handbook for Ceramic, Glass, and Stone Tile Installation

These standards and guidelines are extensive in that they cover many types of installations using tried and true best practices, methods, techniques and materials recommended for a variety of structures and substructures.  I am not able to send these to you, but they are available for purchase at this link: https://tile-assn.site-ym.com/store/ListProducts.aspx?catid=398904

If you are a tile contractor, these standards will be your guide for all of your tile installations.  I encourage you to purchase them and become familiar with them and use them in your installations.  In addition, I encourage you to explore membership in the National Tile Contractors Association.  More information can be found here:  https://tile-assn.site-ym.com

If you are an owner considering accomplishing a tile installation, I strongly encourage you to interview and hire a qualified, certified contractor and installer who owns, understands and uses the tile industry standards I listed above.  Please research the below links to locate an NTCA Member contractor and CTEF Certified Tile Installer near you.

Why Hire an NTCA Contractor: https://tile-assn.site-ym.com/?page=whyhire

Locate an NTCA Contractor: http://tile-assn.site-ym.com/search/custom.asp?id=2759

Why Hire a CTEF Certified Tile Installer: https://www.ceramictilefoundation.org

Locate a CTEF Certified Tile Installer:  https://www.ceramictilefoundation.org/find-certified-tile-installers

I hope this helps.

Mark Heinlein,

NTCA Training Director

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

Member Question:

I need installation guidance to install a ceramic or porcelain tile over a concrete slab/sidewalk. This will be outside of a church and it is currently a concrete floor and curb. What would you recommend we use at the edge and expansion joints?

Mark’s Response:

There is a lot to consider before tiling a project like this one.  Since you may not have yet received your 2017 TCNA Handbook, I have attached a couple of photos of two methods (F101 and F102) that may be most applicable to your installation.

F101 describes an on ground concrete substrate with proper drainage below the slab, bonded mortar bed, ceramic tile and optional waterproofing / crack isolation membrane.

F102 describes an on ground concrete substrate with proper drainage below the slab, cementitious bond coat and optional waterproofing / crack isolation membrane.

Both of these methods will require proper drainage beneath the slab and drainage for surface water runoff from the finished surface and further drainage into the landscaping.  If the slab abuts a permanent structure, you will want to be certain that the drainage is slope away from the structure – the general rule would be 1/4” vertical slope per 12” of horizontal run.  Besides methods F101 and F102, there may be other methods and materials that will help with system drainage if that is an issue.

Prior to proceeding you will need to determine if this is a well cured slab and whether it is dimensionally stable and free of cracks, films, curing compounds, sealers, etc. and whether it’s surface has been at least steel troweled with a fine broom finish suitable for mortar to bond to it.  The flatness requirements of 1/4” per 10’ must be met for application of an F101 Thick Mortar Bed or for F102 direct bonding of tiles less than 15” on one side.  For direct bonding of tiles with one side 15” or longer the slab must meet the 1/8” per 10’ flatness requirement before the tile (or membrane) is to be set.

You will see that both of these methods list a membrane as optional.  Inclusion of a membrane will help with waterproofing above the substrate and a degree of crack isolation from minor existing or future in-plane cracks.  If the slab is abutted to a structure, I suggest looking for a way to flash the membrane up the side of the structure, potentially beneath the siding (if any).  The “Membrane Options” section of the method lists the specific membrane requirements and also points to Handbook methods F125-Partial / F125 – Full for crack isolation.

Some membrane manufacturers state that their membranes will be able to span certain types of joints if installed per their instructions and as part of a full system warranty (use of one manufacturer’s mortar, grout, membrane, sealant, etc.).  Installation of a membrane will help with waterproofing, some system drainage, and to protect against efflorescence from the substrate.

The “Materials” section defines the specifications for the tile and setting materials to be used in this method.

You are correct that this installation will need Movement Accommodation Joints.  TCNA Handbook Method EJ-171 provides the details.  As a minimum, those joints should be placed around the perimeter and at every change in plane or where the tile meets a different material.  Expansion joints in the concrete slab must be honored upward through the finished surface of the tile.  Expansion, Isolation, Construction, Contraction and other joints must be addressed.  For an exterior installation, joints throughout the tile field are required every 8’ – 12’ depending on materials and environmental conditions.  Appropriate joint width must also be determined based on environmental conditions the installation is expected to be subject to.  Sealants complying with ASTM C920 with an appropriate designation for this type of installation will be required for the soft joints.  As this is a traffic area, a sealant with a shore A hardness rating of 25 or greater should be considered.  Conversely, a manufactured joint may be available to use.  As we discussed in our workshop, it is the responsibility of the design professional or engineer to determine the location / placement / width / construction of these joints.  Method EJ-171 provides details on constituting these joints – but is too much information for me to forward in this e-mail.

Since this is an exterior installation with some potential of freeze/thaw cycling, expect there to be some system / component degradation over time that may require routine maintenance.

You will want to finish and protect the exposed edges of the tile with a commercially rated, durable metal trim such as brass or stainless steel. Bullnose, or tiles that have been custom bullnosed for the project may also work well depending on the expected use and conditions.

I hope this helps point you in the right direction.  You should have your new 2017 TCNA Handbook soon so you can refer to these methods and all of the other great guidance it contains.

Mark Heinlein

NTCA Training Director

TECH TIP TUESDAY: Q & A WITH NTCA TRAINING DIRECTOR MARK HEINLEIN

Consumer Question:

The concern that I have at this time is the installation of soft joints at the change of plane in the corners of the tub surround. The product is a 12″ x 24″ marble.

 

 

 

 

 

 

 

 

 

 

 

The tile pieces most definitely butt up against one another and it is my belief that the tile installer is going to place a bead of caulk up along the exposed surface of the two.
I am concerned this is not a soft joint to allow for movement of the tiles, but rather a bead of caulk to hide the connection (more aesthetic than functional).  Would this be a concern for you? If so, what types of issues may I have in the future if there is no soft joint?

 

Mark’s Reply:

Thank you for contacting the National Tile Contractors Association!

The Tile Council of North America Handbook and ANSI Standards require functioning open movement joints at changes in plane.  If those joints are tight butted there will be no room for them to properly function to absorb the natural flexing, movement, expansion and contraction that is inherent in all construction.  Without being there in person I am not able to comment definitively however, the joints in your photos do appear to be either tight-butted or have too tight of a joint.

Movement joints at changes in plane are required and are functional and should be filled with a flexible sealant appropriate for the area it is being used.  For a wet environment such as a shower, an ASTM C920 sealant such as a 100% silicone or urethane can be used. These sealants are manufactured to match as closely as possible the grout color.

Before applying the sealant in your marble installation, a test sample should be done along the edge of a scrap piece of marble.  Some colors of sealants have colorants that may absorb into the soft stone and may cause staining that can be visible along the edge of the tile. This is a common pre-installation test that should be done with all marble installations.  A phone call to the technical department of the sealant manufacturer may help determine which of their colors are best suited for soft stone.

The best way to find an NTCA Recognized Consultant in your area is to review our list at this link:  http://www.tile-assn.com/?page=recconsultants. These are highly regarded consultants that may travel regionally or nationally.  Feel free to let them know about the conversations we have been having.

I hope this helps.


Mark Heinlein, NTCA Training Director

TECH TIP TUESDAY: Q & A WITH NTCA TRAINING DIRECTOR MARK HEINLEIN

Contractor Question:

Mark,
I am thinking about putting a heating TapeMat in the floor of my bathroom.  The manufacturer’s literature suggests a modified thin-set mortar.  I am using a large format tile (12” x 24”).  I am placing the tile on a 3/4 inch plywood subfloor with a 1/4 inch Hardy board backer.  The floor is supported by 2”x12” floor joists spaced at 16” on center.  The bathroom is L shaped and is  8’x4’ with a 3’ L.  The 8’ wall is an exterior wall. Would an unmodified mortar work as well? Is it even advisable to use a modified mortar with a large format tile?

Mark’s Reply:

Thanks for the info.

Assuming ceramic/porcelain tile is being installed, the industry recognized method found in TCNA Handbook is RH135-16.  The method describes the details for an electric radiant heat system encapsulated in mortar over backer board on a plywood subfloor with joists 16” on center, which is the installation you have described.

It sounds like you are not installing a waterproofing membrane in the system.  In that case, the required thinset mortar for the cementitious bond coat is an ANSI A118.15.  In other words, an Improved Modified Dry-Set Cement Mortar is required.

The mortar you select should have the words “Meets ANSI A118.15” stamped on the package.  Be certain to carefully follow the mortar manufacturer’s instructions for the proper amount of water, mixing instructions, slaking time, open time, etc.

You asked whether it is advisable to use a modified mortar with a large format tile.  It is.  In fact, many manufacturers are now producing highly modified mortars specifically designed for Large and Heavy Tile.  You may find mortars labeled as “LHT” for this reason.  These mortars have specific properties to support the installation of large and heavy tiles on floors and walls.  Some allow for a thicker bond coat.  This is the type of mortar I would look for when installing an electrical heating tape mat system in the bond coat layer.

If you are using a membrane in the system, it may be advisable to use a less highly modified mortar (such as an A118.4) or even an unmodified thinset mortar (A118.1).  Check with the manufacturer of the membrane for their specific mortar recommendation.

Please make certain the surface of your plywood subfloor is flat to meet the industry standard tolerance of 1/8” in 10’ as required by ANSI A108 before you install the backer board.  This will ensure you have a flat finished tile surface on your large format tile installation.  Use a rapid setting patch material to fill low spots and a belt sander on the high spots of the plywood.  Do not use more or less thinset to help you flatten your installation while you set tile.  Doing so will prove problematic for you and your installation.

Membership in the National Tile Contractors Association is a valuable resource for any professional tile contractor or any contractor who installs tile.  NTCA is committed to improving installations and performance of contractors throughout the tile industry.  Our primary mission is training based on the tile industry standards I have described above.  Every installer should own and be familiar with the standards, methods and details that guide the tile industry.  I would be happy to discuss with you and your tile installation contractors the many benefits of membership in NTCA.  Please feel free to contact me, or Jim Olson at [email protected] for more information.  Also please visit our website at www.tile-assn.com.

The Ceramic Tile Education Foundation (CTEF) supports education and training in the tile industry.  The Certified Tile Installer (CTI) program is a highly sought after certification for tile installers who wish to achieve a higher level of professionalism and recognition in the tile industry.  Please visit the CTEF website at https://www.ceramictilefoundation.org to locate a Certified Tile Installer or contact Kevin Insalato at [email protected] for more information on how a contractor can become a CTI.

I hope this helps.

Mark Heinlein, NTCA Training Director

 

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