Surface Finish, Leveling, and Tolerance
What the candidate must know
This domain tests finished-surface quality: flatness and levelness, tolerance limits, and finish type. Concepts: specified tolerance (for example, deviation under a straightedge over a stated length), level versus slope (floors may be specified to drain), surface texture (troweled, floated, brushed), and how to correct minor high spots without weakening the floor. Know that tolerances are measured with defined tools and methods, and that "looks flat" is not a measurement.
Traps
Frequent traps: applying a thin leveling skim to fix a low area (weak, prone to delamination); assuming a floor specified to drain must be perfectly level; and measuring tolerance with the wrong tool or over the wrong length. Questions may also test whether high spots can be ground down - usually acceptable within limits, but excessive grinding exposes weaker material. Watch for confusion between flatness (no bumps) and levelness (overall plane).
Worked example / rule of thumb
Rule of thumb: check tolerance with a straightedge of the specified length placed in multiple directions, and record the maximum gap. Example: if the specification allows a 3 mm gap under a 3 m straightedge and you measure 5 mm over a low area, the fix is to rework the area with compatible material while it is still workable - not to fill the gap with a thin skim after cure.