Finishers must hit the gap in the window of finish ability to avoid which pair of problems?

• A. premature finishing, late finishing
• B. surface crusting, delamination
• C. cracking, spalling
• D. shrinkage, curling

Answer: (A)

The main idea is the finishability window—the period when the concrete surface is at the right consistency to be finished effectively. Finishing within this window helps you avoid problems that come from doing it too early or too late. If you finish too soon (premature finishing), you push bleed water and fines up to the surface, creating laitance and a weak, dusty layer that can weaken the finish. If you wait too long (late finishing), the surface stiffens and becomes harder to work, leading to uneven texture, trowel marks, possible tearing, and bond issues with subsequent work. So, finishing within the right window avoids both premature and late finishing, which is why that pair is the best fit.