Which is the most common method for measuring slab flatness and levelness on a project?

• A. Use F-number ratings (FF/FL) and straightedges or profilometers as specified by project documents
• B. Visual inspection only
• C. Measure with a laser level alone
• D. Count the number of cracks

Answer: (A)

Slab flatness and levelness are quantified using FF and FL ratings, which are measured with a profiling device or a long straightedge as defined by project documents. This method provides objective, repeatable numbers that reflect the actual surface geometry across the slab, and the project specs specify the target FF/FL values and how to measure them. Visual inspection alone can’t quantify how far a surface deviates from perfect flatness or levelness, and a laser level by itself typically doesn’t capture the full, continuous surface profile needed for FF/FL assessment. Counting cracks addresses cracking damage, not the surface geometry being measured.