So what’s happening with all these larger format tiles? More lippage. Now, you might think if the substrate is flat you shouldn’t have to worry about lippage, right? Not exactly. What we’re also faced with is the tile/stone itself is not perfectly flat. So combine this with the larger tile sizes and small grout joints, and you end up with lippage.
That’s to say nothing of the running bond or brick joint offset patterns that are very popular. Are your customers requesting a 50% offset/stagger, or are they willing to go with what the industry recommends, a one-third offset on larger tile?
The one-third offset should not be news to you if you know the standard. Here’s an excerpt from ANSI A108.02 Section 4.3.8 regarding grout joint size, particularly in relation to the tile size, dimensional precision and offset pattern: “184.108.40.206 Running bond/brick joint offset states that where the side being offset is greater than 18” (nominal dimension), the running bond offset 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.”
Here are some additional excerpts, from the Tile Council of North America (TCNA) Handbook for Ceramic, Glass, and Stone tile installation, addressing flatness and lippage. Lippage refers to differences in elevation between the edges of adjacent tile modules. The Handbook states these are factors that influence lippage. “Allowable thickness variation in accordance with manufacturing standards. Allowable warpage of tile modules. Spacing or separation of each tile module, which would influence a gradual or abrupt change in elevation. Angle of natural or manufactured light accentuating otherwise acceptable variance in modules. Highly reflective surfaces of tile modules accentuating otherwise acceptable variance in modules.”
So how much lippage is considered acceptable? The TCNA Handbook states: For pressed floor and porcelain tiles with a joint width of 1/16 to less than 1/4”, the allowable lippage is 1/32”. For 1/4” or greater joint, 1/16”.
Now we know the acceptable lippage, but what about floor flatness? We again turn to the TCNA Handbook:
“Subsurface Tolerances for Thin-Bed Methods. For thin-bed ceramic tile installations with tiles at least one edge 15” in length or longer, maximum allowable variation is 1/8” in 10’ from the required plane, with no more that a 1/16” variation in 24” when measured from the high points in the surface. Thin-bed stone tile installations: maximum allowable variation in the tile substrate is 1/8” in 10 feet.
“For Mortar Bed Methods. For subsurface tolerances with the thick-bed mortar, or self-leveling methods, maximum allowable variation in the installation substrate is 1/4” in 10 feet.”
You can almost guarantee floor preparation of some sort with these tolerances, due to the lack of flat concrete slabs and wood subfloors. Fortunately, there are several systems available to help the tile setter to minimize the potential for lippage. These systems work on floors, walls, and ceilings.
Keep in mind these systems do not take away the need to have a substrate that meets flatness requirements. All of the systems mentioned have different sized plates or are able to accommodate different thickness of tile and stone. Let’s take a look at some of these products.
The Mechanical Lippage Tuning system (MLT) utilizes a bottom plate with reusable stems that attach to the plates (Photo 1). This system allows the user to remove the tension locking cap and move the stem if necessary without having to “break away” the base and stem by sliding the cap to release. When in place, the setting/removal tool is used to tighten down the cap (Photo 2). Once the mortar is dry, the setting/removal tool is used to disengage the stems, which are then ready to use for the next installation The company also has rubber pads that are placed under the tension locking cap for thin tile, unglazed or highly polished materials to prevent scratching. Photo 3 shows the lippage system in place. Photo 4 is the finished product.
The Tuscan Leveling System is available in two different systems. The first one has a single-piece base and stem (Photo 5). The nylon stems require a one-time soaking in water at room temperature for two hours, or lukewarm to hot for 30 minutes. Soaking is done to maximize the elasticity of the stem when tension is applied. The cap is placed on the stem and the setting/removal tool is used to tighten (Photo 6).
This company also has the Tuscan SeamClip, a one-piece, no-tool-required clip. There are three different colored clips for different thickness of tile/stone. Place the clip base under the tile and when ready, simply press the two flaps towards the center post until they click. Once the mortar has dried, use your foot or a rubber mallet in the direction (parallel) of the joint to break away the cap. This clip is a one-time use and is not reusable. (Photo 7).
Next is one that takes on a new twist, literally: Progress Profiles’ Proleveling System. This system uses threaded stems with a twist-on cap (Photo 8). This manufacturer also has different stems for different functions. To remove tabs on this system, kick or use a rubber mallet in the direction (parallel) of the joint to break away (Photo 9).
The last one we’ll take a look at is the Raimondi Tile Leveling System. This one utilizes a wedge system to minimize lippage (Photo 10). The system uses a baseplate with a slot for use with the wedge. Traction adjustment pliers are used to tighten the wedge into the slot (Photo 11). Once the mortar has dried, remove tabs with a rubber mallet in the direction (parallel) of the joint
There are other manufacturers of these products—too many to mention all of them—but this covers the basic types of systems that are out in the market. Make sure to follow the manufacturer’s guidelines, as there are differences with each product.
Our company has been using lippage systems for our installations for a number of years. Do we use them on every job? No, but when the need arises, we have them. Here’s the way we look at it: If there are products out there that can enhance the quality of our installations we’ll utilize them. Do they have an added cost? Yes, it’s minimal but make sure you have your costs covered when you do your estimates. If you’re still on the fence, think about what that callback is going to cost you if you have to go back to the job to address lippage issues.