When concrete is setting slowly, floating should be performed as late as possible, when the finisher's footprint is barely perceptible.

When concrete is setting slowly, floating should be performed as late as possible, when the finisher's footprint is barely perceptible.

• A. Barely perceptible
• B. 1/4 inch
• C. 1/2 inch
• D. Not perceptible at all

Answer: (A)

Floating is timed by how the surface is setting. When concrete is setting slowly, you want to float when the surface has stiffened enough to support the float but is still plastic enough to be worked. A finisher’s footprint that is barely perceptible indicates this just-right stiffness: the surface can be smoothed and closed without tearing or gouging, and fine materials can be brought up to the surface for a uniform finish. If you float while the footprint is deeper, you risk tearing the surface, pushing laitance or fines unevenly, and creating ridges. If you wait until there’s no footprint at all, the surface may have firmed up too much to float effectively, leading to a harder, less responsive finish or a glazed appearance. So, the best moment is when the footprint is barely perceptible.

Floating is timed by how the surface is setting. When concrete is setting slowly, you want to float when the surface has stiffened enough to support the float but is still plastic enough to be worked. A finisher’s footprint that is barely perceptible indicates this just-right stiffness: the surface can be smoothed and closed without tearing or gouging, and fine materials can be brought up to the surface for a uniform finish. If you float while the footprint is deeper, you risk tearing the surface, pushing laitance or fines unevenly, and creating ridges. If you wait until there’s no footprint at all, the surface may have firmed up too much to float effectively, leading to a harder, less responsive finish or a glazed appearance. So, the best moment is when the footprint is barely perceptible.