Finishing with a steel float: what is one effect?

• A. Increases roughness of the finish
• B. Increases moisture retention
• C. Reduces risk of cracking
• D. Increases staining

Answer: (C)

Finishing with a steel float densifies the top layer of the concrete by pushing the cement paste to the surface and filling the capillary pores. This creates a smoother, tighter, less permeable surface. With fewer open pores, moisture loss during curing is reduced, which lowers the plastic and drying shrinkage stresses that can cause cracking. The result is a finish that's less prone to hairline cracks and crazing, especially when done at the right time and with proper control. The other ideas—making the surface rougher, increasing staining, or merely changing moisture retention in a way that increases cracking—don’t align with what steel finishing typically does.