Finishing window
The period during which fresh concrete is stiff enough to work but not yet set, when floating, troweling, and texturing must be completed.
What does finishing window mean?
The window opens when bleed water has left the surface and closes at final set, and its length varies from a comfortable few hours to a frantic thirty minutes depending on temperature, wind, mix, and admixtures. Working before the window opens builds a weak surface; working after it closes tears the surface. Nearly every surface defect in flatwork traces back to a crew working outside this window.
In practice
Crews size their labor to the expected window, and an accelerated winter mix or a hot windy afternoon can shrink it faster than the crew can adapt.