What does measuring the gap under a 10-ft straightedge determine?

What does measuring the gap under a 10-ft straightedge determine?

• A. Floor Flatness
• B. Levelness
• C. Surface Smoothness
• D. Structural Integrity

Answer: (A)

Measuring the gap under a 10-foot straightedge evaluates how closely the concrete surface matches a flat plane over that span. If the straightedge sits flush, the surface is flat across that length; any gap indicates deviations—high spots or low spots—that detract from flatness. This is the test most directly tied to Floor Flatness, yielding an FF-related assessment of planarity. Levelness, meanwhile, concerns slope or tilt over a distance and is assessed with different methods or longer spans; surface smoothness refers to texture, not geometric flatness; and structural integrity is about strength, not surface planarity. So the gap under the 10-foot straightedge is a measure of floor flatness.

Measuring the gap under a 10-foot straightedge evaluates how closely the concrete surface matches a flat plane over that span. If the straightedge sits flush, the surface is flat across that length; any gap indicates deviations—high spots or low spots—that detract from flatness. This is the test most directly tied to Floor Flatness, yielding an FF-related assessment of planarity. Levelness, meanwhile, concerns slope or tilt over a distance and is assessed with different methods or longer spans; surface smoothness refers to texture, not geometric flatness; and structural integrity is about strength, not surface planarity. So the gap under the 10-foot straightedge is a measure of floor flatness.