Large tile needs a flatness line
An estimate for large modules has to add two sentences a small-tile estimate can omit: how flat the substrate will be made, and how the height difference between adjoining edges will be controlled. Large tile follows the plane under it. Naming only the tile size has not described the installation.
Lippage is an edge step
ANSI A108.02 section 4.3.7 defines lippage as the difference in elevation between the edges of adjoining tile. The Tile Council lippage FAQ says a thinset installation over a substrate that is not flat often cannot meet the lippage limit, because the tile follows that plane. The estimate should say what flatness work happens before thinset, in words that name the operation. The words "large format" are not that sentence.
Name the control method
The second sentence says how the edge step will be managed while the tile is set: a leveling system, a mortar bed, or another method the estimator is actually proposing. Clips do not flatten a ridged floor by themselves. The flatness sentence and the control sentence answer different failures, so one of them cannot stand in for the other.
Warpage stays on the tile
The same FAQ says allowable lippage uses the warpage the tile actually has, plus the table allowance, and that actual warpage still has to stay inside the manufacturing limit. The estimate should not treat the manufacturing maximum as a second number added on top. This page does not set a company tolerance. It says the estimate has to contain the flatness line and the control line.
Fetched 2026-10-11 from the Tile Council lippage FAQ. The standard sentences follow that page. They are not a company tolerance.
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