Large-format floor tile is being installed over a slab with visible humps. The tile setter says extra thinset will flatten the floor as work proceeds. What should the superintendent require?
Correct Answer
D) Correct substrate flatness to the tile manufacturer's and project requirements before setting
Large-format tile requires a properly flat substrate; using thinset as a leveling bed can cause poor support and lippage. Other choices hide or create a finish defect.
Why This Is the Correct Answer
Large-format tile requires a properly flat substrate; using thinset as a leveling bed can cause poor support and lippage. Other choices hide or create a finish defect.
Why the Other Options Are Wrong
Option A: Start setting tile and grind high corners later, leaving tile lippage unverified
In finishes, Start setting tile and grind high corners later is the wrong selection for Tile lippage: the choice would not get the project to Correct substrate flatness to the tile manufacturer's and project requirements before setting, which is the Tile lippage result verified by the source.
Option B: The superintendent should use more grout to hide height changes
The trap in B is Use more grout to hide height changes. That selection is wrong because it leaves the work at an informal or incomplete stage, while Tile lippage requires Correct substrate flatness to the tile manufacturer's and project requirements before setting; Tile substrates must meet specified flatness before tile setting begins.
Option C: Accept lippage because large tile is never flat
Choice C gives Accept lippage because large tile is never flat. Its specific error: it points to Accept lippage because large tile is never flat, but.
Memory Technique
Remember tile lippage by its jobsite consequence: the correct move points to Correct substrate flatness to the tile manufacturer's and project requirements before setting.
Reference Hint
Open Principles and Practices of Commercial Construction, 11th Ed., 2024; use the index entry or section for "Tile substrate preparation and flatness" to confirm that Large-format tile requires a properly flat substrate; using thinset as a leveling bed can cause poor support and lippage.
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