Tile and Stone Lippage: What is acceptable (and how do you specify it?)

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Photo courtesy Premier Tile

by Donato Pompo, CTC, CSI, CDT, MBA
Lippage is the vertical displacement between two adjacent tiles of a ceramic, glass, or stone installation. When excessive, this can lead to numerous problems, ranging from chipped edges to snagged furnishings and appliances to safety hazards.

There are industry standards for determining whether the amount of lippage is acceptable or excessive. American National Standards Institute (ANSI) A108.02-2013, General Requirements: Materials, Environmental, and Workmanship, Section 4.3.7 (“Lippage−Guidelines, Explanation, and Caution”) deals with what is allowable ceramic tile lippage and how to avoid excessive lippage. It states for grout joints that are less than 6 mm (1⁄4 in.) wide, the allowable lippage is 1 mm (1⁄32 in.), plus the inherent tile warpage. For grout joints 6 mm (1⁄4 in.) or wider, this becomes 2 mm (1⁄16 in.), plus the warpage. On the other hand, in the 7.2 edition of Marble Institute of America’s (MIA’s) Dimension Stone Design Manual (p. 14-3 “Horizontal Surfaces/General Notes,” Section 4.0−Lippage) simply says lippage should be limited to 1 mm (1⁄32 in.) for natural stone tile installations.

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The challenge in trying to minimize tile lippage has to do with numerous compounding conditions, including the substrate’s flatness, which can have significant effect particularly when one is adhering directly to a concrete slab. Per ANSI A108.02-2013 Section 4.1.4.3.1 (“Horizontal Subfloor Surfaces”) and .2 (“Vertical Surfaces”), the substrate needs to be prepared before the tile installation such that the maximum allowable variation from the required plane for tiles with all edges shorter than 380 mm (15 in.) is no more than 6 mm in 3 m (1⁄4 in. in 10 ft), and no more than 1.6 mm in 0.3 m (1⁄16 in. in 1 ft).

For tiles with at least one edge 380 mm (15 in.) or longer, the maximum allowable variation from the required plane is not more than 3 mm in 3 m (1⁄8 in. in 10 ft), and no more than 1.6 mm in 0.6 m (1⁄16 in. in 2 ft). If the substrate is too irregular, then it is difficult for the installer to compensate for the irregular surfaces and install the tile in a manner to minimize lippage.

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Stone tile installation without excessive lippage—a limestone fountain installation. Photos courtesy Ceramic Tile and Stone Consultants

Medium-bed thin-set mortars
There is an erroneous belief among some tile-installers and specifiers who think using a medium-bed thin-set mortar adhesive—which can be applied as thick as 19 mm (3⁄4 in.)—is designed to compensate for substrates excessively out-of-plane. Industry standards for thin-set mortar adhesives, such as Section 2.1 of ANSI A118.4-2012, Standard Specifications for Modified Dry-set Cement Mortar, says dry-set mortars are designed as direct-bond adhesives. They are not intended to be used in truing or leveling underlying substrates or the work of others. (Due to this common misunderstanding, the industry is in the process of eliminating the name ‘medium-bed’ mortar, and changing it to ‘dry-set mortar for large and heavy tile.’)

Substrates need to be prepared before adhering tiles. High spots on concrete slabs must be ground down and low spots filled with special patching mortars or cementitious self-leveling mortars to achieve the appropriate flatness or slope. Medium-bed mortars are only meant to be used for large and heavy tiles so they do not sink into the thin-set mortar during the installation; they can also be used to compensate for ungauged tiles that vary in thickness from each other.

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10 comments on “Tile and Stone Lippage: What is acceptable (and how do you specify it?)”

  1. I’ve noticed that in some homes I’ve been in, that there is significant lips on the edge of tiles. I do think it is important that there is a slight lip, but nothing too big. Having one too big would be a home for dirt and other things to get caught in. Just be sure if you are doing something like this yourself, that you do it to the proper specifications.

  2. What percentage of floor tiles that are at the 1/32″ limit for lippage, is acceptable? In 340 Sq. ft. we have 40 spots that are at 1/32″ lippage and 8 spots that are above. I have yet to see the percentage question addressed. Imagine a floor where all tiles are at 1/32 lippage. Would it technically be acceptable? With the above specs our floor looks terrible. we can”t even push our kitchen chairs under our table without having to lift them>

  3. My Question is similar to Mike B.’s. I have a 2000sqft house that is tiled throughout. Nearly each tile has at least one adjacent tile that is uneven (i.e., there is lippage throughout the house) and I would be hard pressed to find a tile with an no lippage. The RESIDENTIAL PERFORMANCE STANDARDS GUIDELINES states: “…Lippage greater than 1/16″ is considered excessive…except where…tile [is] larger than 13 × 13 inches.” My tiles are about 20″. For me, it is not that there is lippage, but the fact that there is lippage THROUGHOUT the house. What is the corrective measure for this?

    1. There is no percentage of tiles with lippage in excess of the ANSI standard stated. I guess the installers are expected to complete the job with no lippage beyond what is allowable. This is the same as other floor covering categories. Manufacturers have a realistic 5% error rate but installers, as the final quality control step, have no acceptable error rate. They could always follow the NAHB performance guidelines which are more forgiving for imperfect situations.The NAHB, as stated by Mark S. does not even list an acceptable lippage measurement for tiles larger than 13″. Maybe whatever lippage is present is acceptable to them? As stated in the article, there are usually several contributing causes for the final lippage.

  4. There are tiles that are sunk in lower that the adjacent tile. What is the remedy to laying them even. We would like these tile removed and reinstall. Is it possible if tile is pulled it will make the floor weak and the other tiles may become loosen. So disappointed in the overall job. About 20% of the floor has lippage.

  5. You are joking right when you fix a tile bigger than 600 mm long they don’t make them straight so you will always get lippage if you want no lips buy a vinyl floor

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