Which device or method is commonly used to assess slab flatness and levelness on a project?

• A. Straightedges and profilometers
• B. Digital calipers
• C. Moisture meters
• D. Thermal imaging cameras

Answer: (D)

Assessing slab flatness and levelness relies on measuring surface elevations across the slab to detect deviations from a perfect plane. Straightedges provide quick, on-the-spot checks over longer spans to spot obvious high or low spots, while a profilometer (slab profiler) sweeps across the surface to record a precise elevation profile. From these measurements, FF (flatness) and FL (levelness) values are calculated to quantify how flat and level the slab is against standard tolerance ranges. Digital calipers only measure small distances and can’t cover a large slab area. Moisture meters assess moisture content, not geometry. Thermal imaging cameras map temperature differences, which can hint at issues but do not quantify the surface’s geometry. Therefore, straightedges and profilometers are the typical tools used to evaluate slab flatness and levelness on a project.