Are tight miters the right miters for your project?

Sharp corners, especially in shower installations, can be safety hazards for end users

Mitering: a hallmark of a tile installation and a craftsperson’s skill. The tighter the miter, the greater the skill, the finer the installation.

But is a tight miter what the end user really needs? Is it good for the life of the installation? Is it even safe?

Sometimes $100 bills are used to show a nice, tight miter joint width in photos.

We all know the NTCA Reference Manual is a rich resource of technical tile information that is constantly being updated. The NTCA and members of its Technical Committee care deeply about their fellow tile contractors and the success and safety of our industry. The 2020/2021 edition of the NTCA Reference Manual includes a new section (pages 172 – 173) dedicated to performance and safety precautions when mitering tile and stone. NTCA Five-Star Contractor Woody Sanders of D.W. Sanders Tile & Stone Contracting in Marietta, Ga., knows the concerns and challenges with mitering and led a committee to craft this newly-published section. I recently had the opportunity to spend some quality time with Woody talking mitering and the process of crafting this section for the NTCA Reference Manual.

I don’t need to re-hash for you everything the NTCA Reference Manual says about mitering. It’s a heck of a lot better if you just crack open your copy to pages 172 – 173 and read the new section for yourself. 

I do want to discuss the fact that tight miters are not necessarily the right miters. Woody and I see lots of examples of amazing tile craft skills illustrated by photos that show tight inside and outside miters, sometimes where $100 bills are used to show the nice tight joint width. Super nice. But always appropriate? Here are some excerpts from my conversation with Woody.

Woody Sanders
Miters in strip glass and large-format tile in a wet area.

Mark: Why did we need a section about mitering in the NTCA Reference Manual?

Woody: There are many reasons, primarily: aesthetics; safety; proper installation practices; structural stability; long-term performance of the installation. In a wet area especially, safety is paramount.

Mark: One of the hallmarks of a modern tiled shower is that it is a one-of-a-kind, hand-crafted appliance. That means there are usually lots of niches, benches, short walls, alcoves – you name it. All of these are prime locations for miters, making showers the place where an installer can really showcase their skill.

A tight miter works well for a dry area backsplash.

Woody: That’s right. A shower is the place where a gifted installer and smart contractor can make good money. The problem comes when aesthetic considerations become safety hazards. Sharp, tight miters may look great for the photo-op but every installation must be created with full consideration for the end use and end user. Here’s the problem – a shower is one of the highest slip/fall hazard locations there is. Slip and hit your head on a sharp corner or three-way miter and you might not have a good medical outcome. 

Here’s the other problem – Modern buildings are designed to move. Walls move, floors move, the individual layers of a tile installation move independently of each other. When this movement occurs and there is no room at the miter joint to allow for that movement action, the tile will break, the bond will break – something will break. When it breaks, it will not look as pretty as it once did. In a wet area, the break will open access for water to enter. When water enters the system it can become an agent of destruction.

As tile contractors and installers, when we build a shower, we are creating a one-of-a-kind, hand-built plumbing fixture. We need to understand that we have to manage ALL of the water that enters the shower and direct it to the drain/waste/vent system. Bond coat coverage is very important in a wet area. It is not easy to get 95% or better bond coat coverage when trying to create a really tight miter joint. If bond coat coverage is sacrificed to create the joint, an opening for water to pool and weaken the system is created. That beautiful joint will not look so pretty with use and time.

These sharp miter edges can create a safety hazard when used in a shower, where slipping is common.

Mark: Have you actually seen personal injuries caused by sharp miter joints?

This highly-detailed miter is installed in a dry area, cut in glass tile with the correct blade.

Woody: Yes, I have. Lacerations and cuts. I wanted to use the word laceration in the NTCA Reference Manual, but my committee had to talk me down. Think about it this way – How many tile installers do you know that don’t have cuts on their hands?

Mark: How long did it take to get this section published?

Woody: About a year. It was introduced to the committee of the whole at TISE 2019 where consensus was made to place it on the agenda; a first draft was written and presented at Total Solutions Plus 2019 where a subcommittee was formed to re-shape the draft; the second draft was presented to the committee of the whole at TISE 2020 and was accepted for publication in Chapter 6 – Specialized Installation Procedures.

Mark: Who was on the committee?


Nyle Wadford of Neuse Tile helped with navigating the Technical Committee process and made sure the written words make sense on the page.

Chuck Muehlbauer of the Natural Stone Institute helped with the background of the quirk miter as coming from stone industry.

Mike Hawthorne of the IUBAC made certain we stayed true to ANSI standards.

Noah Chitty and Derek Patterson of Crossville provided input from the tile manufacturer’s perspective.

Jim Harrington of Schluter kept the committee informed on alternatives to mitering.

Mark Albonetti of MD Pro / Prova contributed his wide experience with miters and trim units.

Joseph Mattice of On The Level provided input from an installation contractor’s perspective.

Mark: How wide should a miter joint be?

Woody: The width of the miter joint should match the width of the grout joint in the tile field. If it does not, the aesthetic of the installation becomes unbalanced. Grout joints exist for good reason in all tile installations. They serve as buffers or transitions from tile to tile in the field. We need this buffer of space from tile to tile at the miters also.

This is a good miter joint width created with blunted edges instead of sharp edges.

Mark: Is there ever a correct time to create a super tight miter joint?

Woody: There sure is. We do a lot of work with large stone and panels. We create waterfall edges that are color match epoxy filled, cured and hand softened to create a very pleasing, structurally sound and safe miter joint.

Mark: The NTCA Reference Manual, page 172, talks about quirk miters. These form an external corner with beveled, blunted noses to avoid the sharp edges of the common miter. Tell us about those. 

Woody: Quirk miters are a great way to make a long-lasting, aesthetically-pleasing miter that is safe for users and makes for an enduring installation. The quirk miter concept comes from the stone slab industry. Stone workers understand the strengths and limitations of their materials and they know how to make their miters safe for use and for long-lasting performance. Tile installers should use quirk miters as an excellent alternative to sharp miters.

Mark: Are there any other alternatives to sharp miters?

Woody: Yes. Bullnose and custom-made – even made on site – bullnose are great options. Tile with matching trim pieces are another great way, but they are not as prevalent or available today as they once were. A number of manufacturers also make a wide variety of metal or plastic trim that is set into the bond coat along with the tile. The NTCA Reference Manual discusses modern trim strips as an option. Some modern installations look terrific with the modern trim elements. In many traditional architectural designs clean termination points are critical.

Mark: I have used all of those methods. Each of them takes a lot of skill and experience and time to make for a great looking installation.

Woody: That’s right. Hand polishing, bullnosing, or measuring, cutting and fitting metal trim strips and corners are skills all by themselves. I know some contractors and installers doing beautiful work with these refined skill sets.

Mark: We’ve been talking about mitering for hours. How would you summarize our conversation?

Woody: A mark of craftsmanship is a clean termination point. Look for matching trim. Look to use fused miters. Blunt the miter or use a quirk miter. Don’t miter in wet area. Miter as the last resort.

Mark: Thank you, Woody Sanders, for all you do.

If you know Woody Sanders like I do, you know you can’t have a conversation without discussing the benefits of being a member of our professional association. We talked about the direct access to the resources of our profession and true networking with the people that makes our industry tick.  Woody says it so well: “You get more than you give when you get involved.” And he’s got the stories to prove it.

If you are looking to get more out of your membership, contact me to get involved at [email protected].

Pairing pedestals and pavers in exterior settings

Martin Brookes, Woody Sanders discuss use of pedestal systems in Coverings Connected program

Back in April, when we all thought we would be in New Orleans for Coverings, show management presented a series of highly-informative sessions and webinars in its virtual Coverings Connected Program. 

One such program was Application and Specification of Tile for Outdoor Use, presented by Martin Brookes of Heritage Marble & Tile, Inc., Mill Valley, Calif., and Woody Sanders of DW Sanders Tile & Stone Contracting, Inc., Marietta, Ga. This AIA/CES-accredited session focused primarily on the use of pedestal systems in exterior paving applications. 

This article will touch on many of the salient points of that talk, and provides insight into the advantages and challenges of this technology.

Why use pedestals?

Brookes and Sanders explained that pedestal systems are used primarily in outdoor living systems, when there is a high degree of urban density, and there’s a desire to expand the living space, such as the roof. They provide a Green Squared® certified, lightweight and affordable assembly. They can also be used in government and hotel applications since they provide easy accessibility to under floor wiring or irrigation systems and they are low maintenance – they also make it easier to fine tune tile to eliminate rocking tile or other issues. Plus, pedestal systems can provide a deck that is a little softer to walk on than a hard bonded deck. 

Pedestals can help with drainage, freeze-thaw issues, movement accommodation and pitched air-entrained concrete, providing some control over these issues. In addition, you can reuse tile and pedestals, even if you need to replace the membrane beneath. 

Pedestals and pavers – perfect together?

Sanders got involved with pedestal systems a few years back when he was looking for a better way of doing exterior decks.“This is a great product group, and falls well into what tile and stone installers do,” he said. 

Porcelain pavers with 2 cm and 3 cm thickness are relatively new for U.S. applications, Sanders said, but there are some – from Daltile and Del Conca – that are specifically designed for pedestal systems. These are 24”x24”, 24”x48” and even 8”x48” modules. Other materials can also be used: Indiana limestone, concrete pavers, ipe wood, and even rolls of turf. “We install a lot of ipe wood even though it isn’t tile,” Sanders said. “Fibergrate composite structures allow for some creativity, for bridging, to support turf.”

One factor to consider with pavers on decks is the solar reflectance rating (SRI) – will a light-colored surface in a sunny area be uncomfortably bright; will a dark paver get too hot to walk on?

Working with pedestal systems

Pedestal systems offer a lot of advantages, not the least of which being that pedestals themselves can be made out of post-consumer PVC and offer an environmental advantage. Pedestals can be ordered in a fixed height (a common height is 1/8”) or can range as high as 36” and be adjustable from the base or shim. They offer the ability to handle a 7% change in elevation, though most provide a 2-3% slope. It’s advised to work with the pedestal manufacturer to find the combination of components and features that address the specifics of your project. 

Challenges of pedestal systems

Wind uplift or equalization. Because pedestal systems in effect are a free-floating system, wind can lift pavers and other surfacing material right off decks. Manufacturers have different ways to address this, such as clips or grommets, but sometimes – especially on tall buildings, an engineer is needed. In addition, there are few standards for roof deck systems, and even fewer for pedestal roof deck systems. Another important question to answer on a rooftop install is, “How does the roofer want me to protect roof membrane?” Brookes asked. 

Point loads. A 24”x24” paver weighs 30 lbs. It’s advised that you consult with the tile manufacturer for what the point loads are and their recommended configurations – trays on corners or a five-spot configuration with an extra pedestal in the center? The goal is to ensure the tile makes 100% contact on the pedestal system for full support. It’s also key to be sure that the roof type is compatible with pedestal systems and can support them. Brookes cautioned exercising special care with closed cell foam roofs. “Some do not meet 40 psi criteria to support pedestals,” he said. “Make sure yours does. Be careful with less expensive ones.” 

Roof decks. It’s advisable to partner with a roofing company to do the waterproofing and pitch when working on roof install. Sanders said, “You don’t want to DO waterproofing for roof projects. It’s a very complex and different world. And Brookes added, “In California, I can’t do roofing work, due to state licensing. I have partners who are very well versed in waterproofing and waterproofing systems.”

Sanders related his experience on the roof deck for the CNN project, which presented a challenge in learning the takeoff since isometric drawings weren’t provided to the contractor. “We field verified it and found all the architectural drawings were wrong,” he said. “Falls were wrong, and it was more complex. We wound up with another document with drawing of which pedestals go where and used it with laser level and heights.” Sanders and his crew then had to determine the starting height, with egress specified at the bottom left. They utilized a series of pedestals that ranged in heights/couplers as they grew higher, and created a hand-drawn plan. During the installation process – which entailed two weeks of just assembling pedestals – they used every single component. The process also required two types of layouts – one for pattern and one that established elevation. 

Retainment in this job was also paramount. There was a small parapet already in place, which was absolutely necessary to keep the assembly from falling off the roof. And DW Sanders Tile & Stone did a 100’ mockup to establish how the mechanical, electrical, and plumbing would run through beneath the tile. 


Pedestal systems provide a highly effective, efficient and well-performing system for decking in outdoor spaces, offering several advantages over bonded systems. When should you recommend this system over a bonded tile or stone deck? “We almost ALWAYS recommend this,” Sanders said. And Brookes added, “Almost every deck in high end residential is now a pedestal system.”

Questions about pedestal systems? Contact Sanders at [email protected] and Brookes at [email protected]

East Coast to West Coast templating

Jason McDaniel and Ken Ballin

Templating is often thought of as a technique only used by solid surface fabricators in the construction of kitchen countertops, and other slab stone installations. But tile installers are starting to use some of these same skills to ease the installation process of large panel gauged porcelain tile panels (GPTP), and other intricate mosaic pattern tile installations. 

To research this new trend, I went from one end of the country to the other, finding two well-known NTCA members who employ templating in their businesses. On the East Coast, out of the Garden State of New Jersey, I reached out to Ken Ballin of Skyro Floors. At the other end of the country, in Portland, Ore., Jason McDaniel of Stoneman Construction LLC. Both have a considerable amount of experience with templating. Since they live in different parts of the country and service different markets, they described how templating is used in both. I found it to be an interesting topic and had several questions for each of them.

Describe the general idea, and process of templating.

Ken: The template is used to recreate the space you are getting ready to tile. After creating your template, you lay out the tile on the floor and lay the template over the tile, tracing around the template to mark all of your cuts before the installation starts.

Jason: You are creating a physical map of an area when you template. It works great in this day and age, because of all the unique patterns in tile and all the different types of tile that are out there. 

What materials do you use for your templates? And, where do you get them?

Ken: I like to rip Luan (also spelled Luaun) into 2” strips. It’s easy to find here at most lumber yards and big box stores. It’s somewhat durable and can be used over and over again.

Jason: I use Luan (strips of wood). I would tell any installer to go to a cabinet or stone fab shop to find some. There is a white plastic out there that looks like cardboard that works too, and comes in big panels of 4” x 8” that you can cut down to 3” strips. 

On what projects is templating a good choice? Describe a project you wouldn’t do without a template.

Ken: Templating is great for installation of irregular-shaped tiles, or in irregular-shaped spaces. They work well anywhere precision is required, and measurements are difficult to take. My mind works a lot better visually than with measurements. 

Jason: The 10th floor of a high rise in an apartment complex where you don’t want to carry saws and all of the other things needed to create the floor. Take the template back to the shop, overlay the tile, and trace the outline of the template on the tile. You can cut it and have it ready to take back to the jobsite and put in place. Any time I scribe I use a template. 

Is templating a good idea because it saves time? Or because it gives a better finished product?

Ken: I don’t know that templating always saves time, but for me it’s a way to be more precise without driving myself crazy trying to measure individual pieces. We all think differently, so it is important to do what works best for you.

Jason: It does both; it allows you to know your path. One of the things people often ask is how am I so efficient with my time. If you have a contest and the race is to create a herringbone backsplash, I’d be faster using a template.

Describe your first experience with templating a tile installation, so our readers might know what to expect.

Ken: My first time templating a tile installation was an irregular-shaped bathroom floor going into a curbless shower with a small porcelain plank tile on a herringbone pattern. I got super lucky because somehow during the installation process the layout got tweaked and all my smaller cut pieces around the perimeter were eliminated. It came out fantastic, but to this day, I don’t know what I goofed up on. I don’t mind being lucky every now and then though.

Jason: It was 1” by 1/2” mosaic Carrara herringbone backsplash in a laundry room. It had multiple return walls and a window and wall plates. I remember looking at this space and saying, “I don’t want to be here, I’d much rather be in my boat, so how can I get this done fast?! I bet if I laid this out on the master bathroom floor and templated the space, overlaid it, traced it and cut it, then I could do it all very quickly.” I remember people saying “Wow! How did you do this so fast?”

What are some common pitfalls of templating?

Ken: Templating can be like building a piece of furniture in a room in which that furniture is going to stay. Make sure you can get it out of the room you created it in if you need to! Wood templates only bend so much before the glue gives. Sometimes I’ll make a few smaller templates and butt them together so they are easier to move around.

Jason: One of the most important things to remember is to remove your line from the tile when you trace a template. Another pitfall is not leaving room for expansion. It’s not talked about enough. You have to realize that when you install your tile, the installation is going to grow on you, and you need to account for that. While templating, it can be easy to lose your place on the wall. Sometimes putting indicator lines on the wall and on the template helps, to keep your place. It’s like mile markers.

Explain the benefits of templating on establishing your layout in an installation.

Ken: Templating allows you to lay out your tile and move your template around to avoid small cuts. You can get an idea visually of the total install before you even make a single cut. For people like me who are very visual, it’s a game changer, a great addition to your installation arsenal. You won’t use it every day but when you need it, it’ll make your day a lot easier.

Jason: Templating makes it easier for an installer to lay out a space. If you are doing a unique pattern, it can be hard to find center and using a template allows you to shift the template in any direction to get a visual. Templating allows you to know what is coming 20’ away. It’s a road map of what we are going to create. Sometimes you are running blind in tile, and a template allows you to see the future. It shows you where you are going, and we all want to know where we are going. We don’t want to go blind into anything.

Thank you, Ken and Jason, for sharing your insight on this great tool of templating, I’m sure this information can equip many of our members for challenging projects in the future. Until next time stay safe, and hopefully I will see you on the road. 

Understand the crucial difference between setting tile and building a tile assembly

The hands of the worker are laying the ceramic tile on the floor.

When you bid a job, what are you selling? Are you simply setting tile or are you building a custom tile assembly that you can set tile on that will last?

When you walk onto a site for a consult with a client, you determine how the building is constructed. You may feel the floor roll underneath your feet or in the bathroom, you may smell musty air and see swelling wood. The client asks “how much will it be to lay some new tile here?”

We’ve all heard that question. It’s a simple question, but for skilled installers, it is not a simple answer.

In those quick moments, a skilled tradesperson might have determined that they will need to demo the entire bathroom to studs, replace rotted joists, install new subflooring, flatten the floor, flatten the walls, cover them, waterproof, and install underlayment. All that before you can “lay tile.” Are you able to explain and present that to your client so that you can sell your value? More important still, do you understand the difference between installing tile and building an assembly?

What is a tile assembly?

As yet, there is no official definition of this term, but generally speaking, a tile assembly can be thought of as a collection of components from structure to finish that directly relate to the performance of the tile. Not every component is necessarily done by the tile contractor, but they will all have an impact on the success of the installation.

Let’s take method TCNA B422 in the TCNA Handbook for Ceramic, Glass and Stone Tile Installation as an example. This is a common installation in a shower. While a client might assume that tiling a shower consists of just setting the finish product and grouting, a diagram like this reveals the true complexity of an assembly in a common situation. There are a minimum of seven components in this diagram that are part of the tile assembly. This is completely aside from the design and layout of the tile pattern itself, which is an art in its own right. The correct type of drain, the right bonding mortar, the backing or substrate, membrane choice, appropriate sealant and location, wet area-approved tile, the sloped bed. If any of these steps are improperly executed – or components improperly installed – it could put the entire assembly at risk. Each component requires knowledge of the correct material to use and the method of installation, as well as the order of installation and appropriate cure times of the various materials. Add in niches, benches, and other custom touches and the need for someone who understands these details grows more and more apparent. 

Why is it important?

When we understand all the components of an assembly, it helps us in several ways. 

First, it will ensure the highest chance of success in our installations. Getting things right at each step adds to the lifecycle of the tile assembly. 

Second, it allows us to charge appropriately for the work and time it takes to do it right. If we bid a job without understanding everything that we will have to address, we open the door to lost profit, which is the downfall of any business, large or small.

Third, in educating our clients it gives them the opportunity to make sure that they are getting truly comparable bids. If they understand what goes into an assembly, they will be empowered to make an informed choice as to who they hire. And the person who was the expert and educated them will always be top of mind.

Fourth, when presented with a project drawn up and specified by a design professional (i.e. an architect or structural engineer), understanding the exact terms and limits on where your work begins and other trade’s work ends is invaluable.

Predictable performance protects profits

An underrated advantage of understanding what goes into your assembly is that your installations will perform predictably. This is one reason manufacturers recommend specific products, because they know how they will interact, what the different components do, and the long-term interactions between them.

If you take the time to learn about different parts of an assembly, that will make you a more flexible installer, more efficient, and better able to know how to adapt your knowledge and expertise to new challenges. And it will also enable you to take on installations that you might not have experience in. The resources we have at our disposal such as the TCNA Handbook for Ceramic, Glass, and Stone Tile Installation, the NTCA Reference Manual, and the ANSI A108 documents – in addition to the education we can access from major manufacturers and the Ceramic Tile Education Foundation – are powerful tools we can use to further our businesses, as well as our skills.

So, what are you selling? What are you installing?

Working with face and mesh mount sheet mosaics

It is not breaking news that tiles are made in all colors and shapes and sizes and thicknesses and materials. They each have their own beauty, and tiles of all types and sizes are regularly mixed together to create stunning installations with purpose and function that stand the test of time when properly engineered, specified, designed and installed.

Installation spotted at a public market in Seattle, Wash. 

This article focuses on installing mosaic tiles that have been pre-assembled into a pattern on sheets of mesh, paper or plastic.  But first, a little information about mosaics. 

What are mosaics?

The American National Standard Specification for Ceramic Tile (ANSI A137.1) defines ceramic mosaic tile as: Tile, usually 1/4” to 3/8” thick, and having a facial area of less than 9 square inches. Such tiles are typically mounted in sheets or strips with other mosaic tiles.

Where do mosaics come from?

Many tile manufacturers create mosaic tiles for one-of-a-kind and general pattern installations. The tile industry has a host of notable tile artists who create one-of-a-kind hand-crafted mosaics. By their nature, many tile installers are craftspersons with artistic skills. The Tile Trade Artisans Guild Facebook group is dedicated to encouraging artistry in the trade. Visit it at

How are mosaics mounted?

Artisan created and installed one-of-a-kind mosaic. Photo courtesy of Dragonfly Tile & Stone.

Mosaics can be edge-mounted. Flexible glue is applied to the tile edges, leaving the back of the tile open for full contact with the bond coat. Paper or plastic can be applied to the face of the tile leaving the back open for full contact with the bond coat.

It is important to note that when mesh is applied to the back of the tiles it will become an integral and permanent part of the tile installation. There must be sufficient openings in the mesh netting to allow for adequate, direct contact of the bond coat to the back of the tile. If mesh mount tiles are to be installed in an exterior, wet or submerged installation, the mesh must be suitable for exposure to water.

A common concern with installers is how straight or crooked the mounted mosaics are. It can be tedious work to straighten crooked tiles that are stuck to a sheet. For readers interested in acceptable variations of mosaics mounted to a sheet, open up your copy of ANSI A137.1, study Table 6 and read section 9.5 Test Method For Mounting Variations.

How are mesh and face mount mosaics installed?

First, examine your substrate. Is it flat? If not, stop the installation and start the conversations that lead to making the substrate flat. Is there a membrane in place? This will affect cure time, especially for glass mosaics and plastic face-mounted mosaics.

Proper bedding procedures: For an outstanding description on how to properly bed mosaic tiles (set into mortar), pull out your 2019/2020 NTCA Reference Manual and read pages 108 – 110.

Mesh and face mount mosaic installation instructions:

  1. Check the substrate for flatness.
  2. If the substrate is not flat, make it flat. (Attend an NTCA Regional Training program to learn the skills, tools, and materials to do this.)
  3. Check the area to be tiled for squareness.
  4. Calculate the best, most defensible layout and consider the primary focal point and use. (Attend NTCA virtual and in-person workshops to learn how to do this. For more information, read the Training & Education story in this issue.)
  5. Apply a grid system for the layout to follow.
  6. Clean the substrate.
  7. Dampen dry substrates.
  8. Mix the mortar, following manufacturer instructions.
  9. Key the mortar into the substrate with the flat side of the trowel.
  10. Use the gauged side of the trowel to apply more mortar.  Hold the trowel at a consistent 45-degree angle and trowel the mortar into straight ridges.
  11. Prime the trowel by applying a ridge of mortar along the length of the flat side of the trowel.
  12. Hold the primed trowel at a shallow angle then drag it, flattening the ridges to create a consistent, bond coat layer consistently 3/32” to 3/16” thick (approximately).
  13. Set the tile into the mortar.
  14. Use a solid, flat trowel, float, or similar tool to embed the tile into the freshly troweled bond coat layer. Press well enough to ensure a minimum bond coat of 80% (dry areas) and 95% (wet areas) without forcing excess mortar into the grout joints. Bond coat coverage percentages are for each individual mosaic tile. Pull some tile to check for coverage. Change your trowel size if needed. Practice your technique.

Mesh mount-specific instructions:

  1. After setting the tile and making sure bond coat coverage is achieved, align the tiles to ensure there are no sheet lines.
  2. Insert the long, clean edge of a straight, flat trowel into the joints and use it to align the mosaics within the sheet and align the joints from sheet to sheet. A soft grout float can also be used to shift the tile.
  3. Stagger sheets as you install them to blend the grout joints from sheet to sheet.
  4. Cut squares or rectangles from sheets to overlap sheets as you install them, blending grout joints from sheet to sheet.
  5. Step back from your work and take photos of small sections as you set them. Sheet lines can be much more visible in a photo than when you are focused up close. Examining your work in this way as you go allows you to see sheet lines that you couldn’t while setting and make adjustments while they are freshly set.
  6. Use hard shims, spacers, wedges, or apply tape to the surface to hold tiles in place while they cure.
  7. After curing, clean squeeze-through mortar before grouting and applying sealant at movement and expansion joints and changes in plane.

Paper face-specific instructions:

  1. After setting the tile and making sure bond coat coverage is achieved, align the tiles to ensure there are no sheet lines.
  2. Stagger sheets as you install them to blend the grout joints from sheet to sheet.
  3. Cut squares or rectangles from sheets to overlap sheets as you install them to blend grout joints from sheet to sheet.
  4. Allow the set tiles to cure in place for 15 to 30 minutes (depending on the paper and adhesive).
  5. Apply a damp sponge to the paper face to moisten it and hydrate the glue that holds it to the face of the tile. Don’t get it so wet the paper will fall apart. Don’t let it be too dry so the paper tugs tiles out of alignment while you remove it. Practice.
  6. Pull the paper from one corner or edge of the tile at an angle across the face of the sheet until the paper is off. If the tiles shift or pull out of the mortar – allow the mortar to cure longer and try again. To reduce the amount of pulling force, try using a knife to slice the paper into smaller sections and pull along the short side of the section.
  7. Adjust individual tiles as needed. Insert the long, clean edge of a straight, flat trowel into the joints between tiles and use it to align the mosaic.
  8. Step back from your work and take photos of small sections as you set them. Sheet lines can be much more visible in a photo than when you are focused up close. Examining your work in this way as you go allows you to see sheet lines that you couldn’t while setting and make adjustments while they are freshly set.
  9. Use hard shims, spacers, wedges, or apply tape to the surface to hold tiles in place while they cure.
  10. After curing, clean squeeze-through mortar before grouting and applying sealant at movement and expansion joints and changes in plane.

Plastic face-specific instructions:

  1. After setting the tile and making sure bond coat coverage is achieved, align the tiles to ensure there are no sheet lines.
  2. Stagger sheets as you install them to blend the grout joints from sheet to sheet.
  3. Cut squares or rectangles from sheets to overlap sheets as you install them to blend grout joints from sheet to sheet.
  4. Allow the set tiles to cure in place until firm. Usually at least overnight.
  5. CAUTION: The plastic on the face of the tile will cause a longer cure time for the mortar.  Many mortars cure through the grout joints. Because the
    plastic covers most of the grout joints, the mortar will take longer to cure.
  6. Pull the plastic from one corner or edge of the tile at an angle across the face of the sheet until the sheet is off.
  7. Clean squeeze-through mortar before grouting and applying sealant at movement and expansion joints and changes in plane.

I hope to see your next mosaic installation posted on NTCA’s social media channels! Have fun tiling and I’ll see you next time!

The Hazards of Hybrids

Hybrid Shower

Today’s tile installations enjoy a tremendous amount of flexibility and creativity in methods, materials, and design. While a few decades ago there was only one option for waterproofing shower stalls, today we have myriad options. One tempting method is the Franken-shower, or hybrid shower system. But what risks are there and when is it the appropriate choice?

What is a hybrid?

With topical applications like B421 and B422 in the TCNA Handbook for Ceramic, Glass and Stone Tile Installation, which call for an ANSI A118.10 load-bearing, bonded, waterproof membrane, the membrane extends continuously from the drain to above the showerhead.

A membrane can either be sheet-applied or liquid-applied. Typically, a sheet-applied membrane calls for a 2” overlap at seams, corners, and penetrations. This is usually a band of the same material applied with thinset or an approved adhesive. A hybrid system is a liquid-applied membrane at corners and seams to create the waterproof overlap.

Some contractors who use this method do so simply because they don’t trust the science behind thinset bonding a 2” overlap to maintain a waterproof seal. The internet is replete with videos of contractors conducting their own tests to determine whether or not a system or material is actually waterproof. Other contractors prefer the ease of liquid-applied membranes over a seam. Still, others don’t like the potential build-up of overlapping membranes.

Trust the methods and manufacturers

Photo of hybrid seam installation
Hybrid seam installation. Photo courtesy of Bryan Cook.

That said, one of the most valuable resources we have available to us in the tile industry are ANSI standards and TCNA methods. When we use materials that meet ANSI A118.10 we can trust they will perform as a waterproof system. This being the case, we can and should trust the manufacturers when their materials are installed correctly. And in the TCNA Handbook, we find this language regarding the installation of waterproof membranes: “Bonded waterproof membrane must be continuous, including at changes in plane. Follow membrane manufacturer’s requirements for corners, seaming, and overlap.” Emphasis is mine.

Let’s take a closer look and see what challenges and risks tile contractors take when they build a hybrid shower system.

You don’t know what you don’t know

The first potential issue tile contractors should be aware of is introducing technical unknowns into the system. Potential material incompatibilities may arise when mixing waterproofing systems and materials. 

As contractors, we simply can’t know for sure how different materials will interact with one another. The liquid might require a mechanical profile to grab onto, or the sheet might not allow the liquid to integrate fully into the fabric, thus potentially allowing water to migrate behind the liquid membrane, leading to a failure. Since we can’t speak to the composition of the different materials and how they’ll interact, care should be taken in mixing components from different manufacturers. Ask yourself the following: If there is a failure, where would the fault lie? In the liquid seam? Or in the fabric material? How could that be determined? 

In this case, the failure, and liability, would lie squarely on the shoulders of the installer.

It’s worth noting that some manufacturers allow for a liquid seam mixed with their sheet membrane.  Since they are able to test in a laboratory setting, they can confirm the suitability and compatibility of these installations in their systems. This is key to deciding if a hybrid approach is the right one for your installation. If you prefer building your shower systems in this way, choose a system designed for it.

Partnering with a manufacturer benefits your client

The second issue you should consider is what the manufacturer recommends. A huge strength of our industry is the partnerships between installers and manufacturers. Our trade benefits from the support and knowledge that is available to each and every one of us. Following the recommendations of the manufacturers of the products we use is the simplest step we can take in our partnership.

A popular sentiment and statement is “my word is my warranty.” Unfortunately, it is not that simple. When companies write warranties, they are binding legal language. In other words, if you meet the terms of a warranty, they must as well. And these companies want to partner with us, and so they want to make sure you and your client are taken care of. Manufacturers want to stand with you behind their product. Often, manufacturers’ reps will even go beyond what’s required of them by the terms of the warranty to help installers in the field and to educate them. Of course, as noted above, that may be the start of a long-term partnership between the company and you.

Consider this: in 2020 we suffered an economic shutdown that could not be avoided due to COVID-19. Many small businesses went under, as they could no longer afford to stay in business. Others encountered health issues associated with our trade and must retire early or change careers. If in two years, a client needs a repair on their shower, but their installer is no longer in operation, who will they call? If they believe their shower was built as a system and is under warranty, they will call the system manufacturer. When the manufacturer comes to inspect the installation and determines that an unapproved hybrid system was “designed” by an installer who is no longer in business, what recourse will the homeowner have?

All this is to say we have an ethical obligation as professionals to our clients to make sure that not only is their shower built with proper methods, but proper materials as well. If we “design” our own hybrid system out of materials we happen to like, not only are we assuming all liability on ourselves, but we are actively voiding the client’s warranty, robbing them of their legal rights.

These are vital questions you should ask yourself:

  • Are you introducing technical unknowns into the system, and with them potential failures and health risks for your client?
  • Are you actively voiding your client’s warranty?

Perhaps this won’t change your mind on the subject. However, the fact remains that hybrids come with their own sets of hazards and risks.

Update! Respirable Silica Compliance

Hi everyone. I know you are all out there staying healthy, wealthy, and wise by following your local, county, regional, state, and federal guidelines to protect you, your employees, and your customers by preventing that pesky COVID-19 virus from finding its way into your lungs. This made me think this would be a great time to update you on the current state of compliance with OSHA’s Respirable Airborne Silica regulation. Just like COVID, you don’t want those tiny silica particles to build up in your lungs.

Here it is: There is no change.

That’s right. No change – yet. As I’m sure you know, the gears of government sometimes grind slowly, which seems to be happening with this regulation. In my experience, this usually means that those in charge of a program are taking a long, careful look before making changes to regulation while people are getting familiar with it.

cPaul Regina, TCNA’s Government Affairs Senior Specialist
Paul Regina, TCNA’s Government Affairs Senior Specialist

I recently checked in with TCNA’s Government Affairs Senior Specialist Paul Regina. Here is what Paul had to say about the state of the regulation:

There has been very little happening on the silica front.

In August of 2019, OSHA issued a Request for Information (RFI) regarding revisions to construction Table 1. The OSHA website says they are currently analyzing the data received during the RFI.

The current Unified Regulatory Agenda, an outline of when agencies believe they will be issuing regulations, indicates there is a Notice of Proposed Rulemaking dated June of 2020. Please see the following links for further information:

OSHA Silica Page:

Silica in the Regulatory Unified Agenda:”

As Paul noted, the primary item being looked at is Table 1. This is where the regulation lists the tasks that can produce varying amounts of respirable airborne silica. Table 1 is too long to include with this article, but you can review it for yourself here:

Let’s take a simple look at Table 1. It has these three columns: 

  1. Equipment/Task
  2. Engineering and work practice control methods
  3. Required protection and Assigned Protection Factor (APF)
  • An Equipment/Task is something you do or a tool you use to perform a task in the process of installing tile. A common example is a wet saw used for the task of cutting tile.
  • An Engineering and work practice control method is the description of how the tool is used to perform the task in a manner that keeps the silica dust at a certain level.
  • The Required respiratory protection and APF column is broken into two parts. Fewer than or equal to four hours per shift, and greater than four hours per shift. Each column will list an APF number ranging from 0 (none) to 25. You add up the APF numbers for all the tasks you do in a shift to come up with a total APF.

Here is one example of how the table works: 

Apprentice installer using engineering controls to perform the task of cutting tile with a saw that has a built-in water delivery system to control or eliminate respirable airborne silica. No mask required.

For the Task of cutting tile, if you use an Engineering and work practice control method of using a saw that came with a built-in water supply system designed to constantly keep the blade wet while cutting (a wet saw), you can run that saw and cut tile with it for the whole shift without wearing a well-fitted, approved face mask designed to keep the tiny silica particles from entering your lungs. See if you can tell how I put this example together when you view Table 1 yourself. 

There is so much information on the OSHA website about this. You really should check it out. The FAQ section is really good. It lists the questions that you and I both have and provides us with answers that aren’t loaded up with too much of that wonky government regulation language. You don’t have to be a safety engineer to figure this stuff out. OSHA is trying to help us all understand.

If you read nothing else, read this direct quote from the OSHA website. Even if you’ve read this before, it’s worth reading again. I know it gets my attention when I am not thinking about this every day.

Crystalline silica is a common mineral found in the earth’s crust. Materials like sand, stone, concrete, and mortar contain crystalline silica. It is also used to make products such as glass, pottery, ceramics, bricks, and artificial stone.

Respirable crystalline silica – very small particles at least 100 times smaller than ordinary sand you might find on beaches and playgrounds – is created when cutting, sawing, grinding, drilling, and crushing stone, rock, concrete, brick, block, and mortar. Activities such as abrasive blasting with sand; sawing brick or concrete; sanding or drilling into concrete walls; grinding mortar; manufacturing brick, concrete blocks, stone countertops, or ceramic products; and cutting or crushing stone result in worker exposures to respirable crystalline silica dust. Industrial sand used in certain operations, such as foundry work and hydraulic fracturing (fracking), is also a source of respirable crystalline silica exposure. About 2.3 million people in the U.S. are exposed to silica at work.

Workers who inhale these very small crystalline silica particles are at increased risk of developing serious silica-related diseases, including:

A tile contractor and installer really should think about respirable airborne silica during every work task they do every workday on every worksite. I’ll guess that you don’t have to think too hard to come up with the tasks that create the single largest amount of respirable silica. That’s right – dry cutting tile or grinding tile or mortar with a grinder that does not have a shroud and dust collection system that includes a 99% efficient vacuum and filter or fixed water supply system.

Many talented installers are doing amazing scribe-type tile work these days. Be sure you are using a saw or grinder with the right water supply-type or shroud and dust collection-type system to avoid breathing in respirable silica. (Photo courtesy of Stoneman Construction LLC)

I see a lot of very talented installers doing amazing scribe-type tile work these days. If you aren’t using a saw or grinder with the right water supply-type or shroud and dust collection-type system, then please think about the task you are performing. Think about what you are breathing in. It’s not COVID-19, but once those tiny silica particles get in your lungs they are never coming out. They are going to keep building up and will eventually make you sick and can even be the cause of what ends up killing you.

If you haven’t yet become familiar with OSHA’s Occupational Exposure to Respirable Crystalline Silica regulation 29 C.F.R. § 1926.1153, here is what you need to do for you and your company:

  1. Check out NTCA’s website and read up on the information and follow the links we have provided to the professional tile community., towards the bottom of the page. 
  2. Download our standard compliance plan.
  3. Create your plan.

After you do that, the rest will follow and will become part of your daily safety habits and work practices.

During an informational session at Total Solutions Plus last year, I had the opportunity to ask an OSHA staff member involved with putting the regulation in place if there is a distinction between commercial or residential contractors and whether they were inspecting residential contractors for compliance. He replied that all contractors and jobsites are subject to inspection. He continued that if they happen to see a residential jobsite under work, they may check to see how things are going. 

At any worksite, the first thing they will ask is to speak to the Competent Person and to see your company’s Respirable Silica Control Plan. What is a Competent Person? A Competent Person is an individual in your company who knows all about respirable crystalline silica and your control plan. This is the person who identifies respirable crystalline silica hazards on your jobsites and who has the authorization to correct them right away.

Want to know why this is important? They figure if you have taken the time to prepare a plan and assign a Competent Person, then you have probably looked at your tasks, work practices, and engineering controls, and calculated your APF and many of the things necessary to comply with the regulation designed to protect you, your employees, other trades, your client, and anyone else who enters your jobsite.

Respirable silica exposure control information available on the NTCA website.

Not only is it the law, but it’s also important stuff for your health and wealth. Be wise, take the time today to review your plan or make a plan. And enter “OSHA” at to keep up to date with the latest announcements issued by OSHA throughout the year.

Thanks for reading. Remember to join NTCA’s training team at a virtual live Program in a region or time zone near you soon. Go to and click on the Education and Certification section to see all of the training programs available to you. I hope you take advantage of these terrific benefits today!

Marble moisture discoloration: don’t blame the stone!

Carrara marble moisture discoloration on shower floors is a common problem that has been experienced by many professional tile and stone installers in the U.S. Cases when white or light-colored stone gets random, blotchy-looking dark spots are often posted and discussed at social media groups and online forums. The lack of technical information on cause and prevention of the above-mentioned problem seems to result in a rapidly-growing rejection of white marble as a finish suitable for wet areas. Stone is often blamed for its “poor quality,” “inappropriate mineral composition” and, thus, its inability to provide predictable results when it is installed on shower floors.

Such opinion is often based on the fact that light-colored marble is subject to moisture discoloration not only in cases when a tile and stone mechanic does obvious installation mistakes such as failure to provide proper pre-slope and/or final slope to drain, clogged weep holes, or not fully collapsed mortar ridges, but also in situations when the installer strictly follows the above-mentioned requirements.

This provides a controversy in the light of the fact that white marbles have been successfully used for wet room applications – for example in Europe – for a long time.

Ten Carrara shower modules were tested, with help and support from many industry professionals. Results showed that most of the problems with light-colored marble arise due to inappropriate installation methods/techniques that often result from the insufficiency of the technical information on this subject.

The research has helped to determine two main methods that, if properly followed, will provide great results for white marble at shower floors.

Method #1: traditional dry pack mortar bed shower pan

Before the surge of the discussed problem in late 2000s, marble was mostly installed in shower floors with a traditional water-in water-out system. A dry-packed mortar bed, consisting of one part Portland cement to four to five parts sand, not compacted too tightly and not finished too smoothly, provides a subsurface of connected and very high porosity allowing water to quickly be “taken away” from the underside of marble mosaic. If stone is bonded to substrate with a basic thin-set mortar (preferably unmodified due to its higher porosity), grouted with a simple grout, has no adhered fiberglass mesh reinforcement (an impervious coating on the back of stone also known as “resin backing”) and is not treated with an impregnating/penetrating sealer, the water absorption, migration and evaporation should not face extra complications. The above-mentioned shower system will provide exactly what it was designed for – a proper water evacuation, both topically and internally. 

Method #2: bonded waterproof membrane shower pan with epoxy adhesive and grout

According to our reasonable testing, the bonded waterproof membrane method also provides great predictable results with translucent stone like marble when it is properly installed with a suitable epoxy adhesive, epoxy grout, and very permeable (breathable) impregnating sealer. While the “dry pack” system enables great drainage and internal water evacuation, the second method provides marble with a highly hydrophobic/water-repellent subsurface, almost waterproof grout joints, and a reduced-to-minimum presence of moisture inside its pores, which enables relatively quick topical water evacuation, evaporation of moisture, and drying of the stone.

The problem with bonded membrane pan systems installed with modified mortar and grout

Integrated bonding flange drains create a little dam around the drain opening; not what you want in your marble tile shower installation. 

It is important to understand that the reduced porosity of modified mortars and many modern “stain-resistant” grouts – as well as the design of integrated bonding flange drains (that creates a little dam around the drain opening) within a bonded waterproof membrane system – not to mention the application of penetrating/impregnating sealers – do not contribute to proper internal water evacuation and evaporation. Water still penetrates the stone mosaics, whether sealed or unsealed, either as liquid or gas/vapor and moisture gets trapped below and/or inside stone. 

Saturation of the anchoring fleece in the top layer of a waterproof sheet membrane or dampening of the cementitious coating of a foam pan only reinforces the moisture discoloration. The close distance from the waterproof membrane to the stone on shower floor with a thin layer of mortar – that is much less porous than dry pack sand – does not allow water to be “taken away” from the underside of stone. If the shower is used somewhat moderately, marble and its subsurface do not get really saturated and can dry relatively quickly. However, if the shower is used “heavily” (for example, by a few people in a row), the chances of stone/mortar/membrane saturation are much higher, causing a gradual moisture entrapment within the shower floor assembly installed with the topical waterproofing method.

All the bonded membrane Carrara modules were constructed with full mortar coverage and 2% slope to drain and only one – installed with the “epoxy” method – has shown incredibly quick drying time (from two to three hours to return to the original light color). Other modules, whether sealed or unsealed, have all shown some sort of moisture discoloration that would not fully go away for days.

Trapped moisture under the translucent glass tile installed over a bonded membrane pan.

Again, the reason for such discoloration is the inability of a bonded membrane system to “hide” moisture entrapment under translucent stone when it is installed with materials that still absorb moisture and are not as highly water-repellent as epoxy. 

This conclusion is indirectly supported by the following remarkably interesting statements found in the TCNA Handbook in regards to translucent glass tile installation: “Bonding translucent glass tiles directly to membranes or other impervious surfaces is not recommended because any moisture trapped between the tile and membrane would be visible. Membranes should be placed behind or below the tile setting substrate where translucent glass tile will be installed” (TCNA Handbook for Ceramic, Glass, and Stone Tile Installation 2019, page 7)

The research on the subject continues. Next step will be testing eight new Carrara marble modules installed with different products within the two above-mentioned methods (“dry pack” and “epoxy”).

Why you need movement joints

Quick and easy ways to achieve them correctly

Hopefully, as a tile installer, you’ve heard a lot about movement, expansion, or movement accommodation joints – and regularly plan them into all of your installations. Unfortunately, too many people who regularly install tile are not aware of their importance. We’re going to explore why they are absolutely necessary – and how to provide them correctly, quickly, and easily. 

The National Tile Contractors Association (NTCA) Reference Manual glossary, provides this definition of an expansion joint (aka movement joint): “A joint through the tile, mortar, and reinforcing wire down to the substrate.” 

An unfortunate example of tented tile. The really sad part of this situation is that the installer did an excellent job, except for the lack of any expansion joints.

By integrating these “stress relievers” into the tile assembly, expansion and contraction takes place without compromising its integrity. But who is responsible to make this happen?

Sadly, movement joints are probably the least-used, most-misunderstood, and often-eliminated part of a tile installation. However, they are one of the most important listings in the Tile Council of North America (TCNA) Handbook under Method EJ171. Without movement joints, failure is lurking in the shadows, waiting to strike. This is true especially on floors with ceramic, porcelain, glass, and natural stone tile that is subject to sunlight, in-floor heat, and/or moisture. Many installations that appear to be well done, will fail. The lack of movement joints gives the tile assembly no room to expand, causing the tile to pop up or “tent,” most times in the middle of the floor. You must allow for this movement in all residential and commercial projects. Movement joints are not optional – they are required.

What the TCNA Handbook says about movement joints

The 2020 edition of the TCNA Handbook EJ171 Movement Joint Guidelines for Ceramic, Glass and Stone clearly states: “The design professional or engineer shall show the specific locations and details of movement joints on project drawings.” 

Regrettably, many people involved in the installation of tile products don’t understand that installed tile moves. If this expected movement is not accommodated, the tile will become rebellious and most likely will become very expensive for the responsible person or company.

In other words, as a tile installer, it is wise to include movement joints on every project. Again however, it is not the installer’s responsibility to design and/or locate these joints. That is to be done by the design professional or engineer.

The attached TCNA Handbook EJ171 detail shows the necessary components of the movement joint:

  • Width that is four times the expected movement
  • Compressible back-up
  • Rounded back-up with no bond to the sealant
  • The depth of the sealant is one half of the width of the joint

I call your attention to the sealant. Notice that the sealant is attached only on the sides of the two adjacent tiles.

The sealant attached to the sides of the tile is able to accommodate in-and-out motion like that of an accordion or a back and forth motion similar to rubbing two hands together.

One critical point here is that the sealant does not contact or bond to the sides and/or bottom of the joint. If the sealant is allowed to do so, it is locked in place and will have zero movement ability. In this case, the insertion of a “Rounded Back-Up,” or closed-cell polyethylene foam backer rod allows the concrete floor to expand and contract, but its primary role is to keep the sealant where it belongs: attached only to the tile edges. 

You will notice that the detail refers to the joint material as sealant. This is done purposely to differentiate it from lesser-quality caulking products (acrylic latex or siliconized latex), which dry hard and do not allow for continuous flexibility. According to the requirements of EJ171 and ANSI A108.01, this sealant must be 100% silicone, urethane or polysulfide.

If you understand these principles and install the joint properly, it will permit the required movement to take place, keeping the tile flat on the floor where it belongs. Certified Tile Installers understand this and can properly install movement accommodation joints.

Quick and easy methods for installing movement joints

Do you think movement joints are complicated or are messy to install? Actually, they aren’t. Here are two methods that will produce excellent results, easily and quickly.

Method #1 for movement joints:

Evaluating a Certified Tile Installer hands-on test, Carothers checks the inside corner of a wall to determine if the movement joint was properly installed. These joints provide the ability for movement to occur between wall to wall and floor to wall applications. 

Install the appropriate-sized foam backer rod into the joint

  • Apply painter’s tape along the tile edges of the joint
  • Fill the joint with 100% silicone
  • Smooth it with a sealant tool, popsicle stick, or plastic spoon
  • Remove the tape by pulling it on an angle toward the joint as soon as the sealant is in place.

Method #2 for movement joints:

  • Insert the appropriate foam backer rod into the joint 
  • Fill the joint with 100% silicone sealant (no need for tape)
  • Spray the sealant and the face of the tile with a mixture of water and dish detergent.

The sealant tool, popsicle stick, or plastic spoon is also sprayed with dish detergent solution, allowing the excess sealant to be easily removed without the worry of it sticking to or smearing on the face of the tile. This technique is something that Certified Tile Installers have to successfully complete during their hands-on test.

Depending on the type of joint specified, the profile of the smoothing tool can provide a joint which is either concave (as shown) or flat.

When should the sealant be applied?

ANSI A108.02 – 4.4.5 states, “Install sealant after tilework and grout are dry. Follow sealant manufacturer’s recommendations.”

As I conduct demonstrations on the proper installation of sealant joints, I often hear this statement, “It can’t be that easy.” It is really that easy. Using this technique will save time, eliminate costly callbacks, make your installers happy, and yield satisfied customers. Sometimes something so simple can provide huge rewards.


The Ceramic Tile Education Foundation (CTEF) provides education and installer certification for professionals working in the ceramic tile and stone industry. Certification programs include the CTEF Certified Tile Installer (CTI) program, that is the only third-party assessment of installer skill and knowledge to be recognized by the tile industry, and the Advanced Certifications for Tile Installers (ACT). CTEF is headquartered in Pendleton, S.C., near Clemson University and the TCNA offices. For more information, visit

The INS and OUTS of layout

When we analyze the results of the Certified Tile Installer (CTI) test, given by the Ceramic Tile Education Foundation, we can see that when individuals fail, it’s most commonly because they are unable to complete the test in the allotted time. Often, that’s because so much time was spent trying to determine layout, and those that struggled with their layout simply did not have time to complete their module.

In real-world situations, layout is essential for achieving a pleasing, even design. In either case, there is definitely a need for training on tile layout. The NTCA’s newest workshop program is designed around this theme, and these are a few of the topics we will be addressing in that new training.

ANSI and TCNA layout guidelines

Both ANSI and the TCNA give us guidelines for layout; this information can be found in ANSI A108.02 Section 4.3, and in the TCNA Handbook section “Field and Installation Requirements.”

Tile layouts should be centered and balanced, like this one, if possible. 

ANSI directs us that:

  1. Tile layouts should be centered and balanced, if possible.
  2. We should not have an excessive number of cuts, with no cuts being smaller than a half tile when possible. 

The TCNA Handbook suggests the same but gives us a variety of situations where these guidelines may not be the best option or even possible in some scenarios. Examples of these are:

  • Considerations of focal points around decorative elements.
  • When the size and configuration of the room and the size of the tile make it impossible to center the layout in all aspects. 
  • Layouts that are continuously flowing to several spaces.
  • The effect the tile layout will have on waste.

Minimum grout joint size  

Another important section concerning layout in the TCNA Handbook addresses minimum grout joint width. The trend in our industry is for larger tiles to be installed with smaller grout joints. The guidelines in the TCNA Handbook can help installers to defend against customers who want smaller than acceptable grout joints or no grout joints at all.

A 1/16” grout joint is the smallest grout joint ever recommended. The minimum allowable grout joint size varies depending on the tile in use and how much one tile differs from another in size. The TCNA Handbook states, “To accommodate the range in facial dimensions of the tile supplied for a specific project, the actual grout joint size may, of necessity, vary from the grout joint size specified. The actual grout joint size shall be at least three times the actual variation of facial dimensions of the tile supplied.” Example: for tiles having a total variation of 1/16” in facial dimensions, a minimum of 3/16” grout joint shall be used.

In my experience as a tile contractor when using natural tile (which has a lot of variation}, the tile manufacturer will often recommend 1/4” grout joints or larger. Using this standard, many calibrated tiles I installed would require a 3/16” grout joint, and many rectified tiles would require an 1/8” grout joint.

Presenting this information as the industry standards and guidelines – and not as your personal opinion – can be beneficial in changing the owner’s perspective.

Running bond, brick joint, or any offset pattern

Considering the location of the offset joints in a brick pattern is an important part of layout and is also addressed in our standards. The TCNA Handbook states, “For running bond/brick joint and any offset patterns utilizing tiles where the side being offset is greater than 15”, the offset pattern will be a maximum of 33% unless otherwise specified by the tile manufacturer. If an offset greater than 33% is specified, specifier and owner must approve mock-up and lippage.”

Since larger tiles have more warpage, installing an offset joint at 50%, the high point of one tile will be next to the low point of the next tile, creating unacceptable amounts of lippage. 

The reason this offset is important is because larger tiles may have more warpage up to a cap designated in ANSI A137.1. When installing these tiles on an offset joint at 50%, we now have the high point of one tile (the middle) next to the low point (the ends) of the two adjacent tiles, which can give us unacceptable amounts of lippage.

System modularity

When laying out certain patterns, it is necessary to use tiles that are modular in nature. Modularity is defined per ANSI A137.1 as “Tiles of various nominal dimensions are sized so that they may be installed together in patterns with a common specified grout joint width.” Verifying system modularity and specifying the allowable grout joint for the pattern of an actual tile to be installed are the responsibility of the design professional. If the tiles are not modular or made for the pattern you will install, there may not be room to account for the grout joint.

If the tiles are not modular or made for the pattern you will install, there may not be room to account for the grout joint.
This diagram of a basketweave pattern illustrates that the tile dimensions must allow room for a grout joint in the measured pattern. 

An example of this is a basketweave pattern. If the tiles to be used were 4” x 8” exactly they would not account for the required grout joint. If the two short sides were exactly 4” and met the long side which is exactly 8”, they would butt tightly to each other. However, if the dimensions of the tile were 3-7/8” x 8” this would allow for a 1/4” grout joint and therefore be modular. That is a very simple example but this same principle would also apply to many patterns that include multiple sizes of tile.

Grid lines

Using a grid system is not the only way to do great layouts, but is a tremendous tool.

One skill set that it seems most every professional tile installer possessed in the past is the ability to lay out an entire floor using grid lines. With this method of layout, the entire area to receive tile is gridded out with chalk lines to show where every tile will be placed before the installation starts. The attached picture shows installation going in this way.

The advantage of this system vs. getting reference lines and using spacers is three-fold.

Using a grid system gives installers a great advantage on the job.
  1. You can quickly calculate the exact size of every cut in the installation before you start and can communicate that information to the owner or responsible party before you begin work.
  2. You can have multiple installers in different areas of a project all working simultaneously, and they will be able to tie into each other’s work.
  3. When tiling continuously around obstacles like an island or carpet inset, you can connect your work more easily.

Movement accommodation joints

Non-linear movement joints can be planned to not disrupt the flow of pattern in a layout. 

One of the leading reasons for tile installation failures is lack of movement accommodation joints. The response installers often give for not installing movement accommodation joints is that these joints create an aesthetic issue that their customer would never accept. There have been changes in ANSI A108.01 that now allow for nonlinear movement accommodation joints, which would not disrupt the flow of a pattern in a layout. Crack-isolation membranes can also be used in accordance to TCNA Handbook method F125. This allows the soft joints to be moved to the adjacent grout joints without disruption to the layout or tile pattern. With proper planning in coordination with the owner and design professional, a layout that looks great and has the appropriate movement accommodation joints is more possible than ever before.

We will discuss this information and much more in our upcoming NTCA Workshops. At our in-person events, we will have a variety of stations for hands-on layout training. In addition, keep an eye out for notices about our local NTCA Virtual Workshops, sponsored by a host in your area. These virtual workshops will be set for the dates of the original physical workshops that had to be temporarily put on hiatus. These will be given in webinar format, and will offer opportunities to type in questions about the material being presented.

To see a list of our virtual and in-person training events, go to the Education & Certification tab on the NTCA website.

Stay safe, and I will look forward to seeing you on the road soon.

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