What is the difference between a floating finish and a trowel finish?

• A. Floating leaves a rougher surface than trowel
• B. Floating provides a sealant finish
• C. Trowel finish adds air voids
• D. Floating compresses and levels the surface to remove small imperfections; troweling further densifies and produces a smooth, hard finish

Answer: (D)

Finishing a concrete slab involves two steps that build on each other to create the final surface. Floating uses a float to level the surface and smooth out small imperfections, bringing up the cream and leaving a workable, slightly textured finish. Troweling then uses a steel blade to push more cement paste to the surface, densifying it and closing micro-voids to produce a smooth, hard, less porous finish. So the floating step is about leveling and smoothing irregularities, while the trowel step tightens and smooths the surface for a tougher, more refined final look. The other choices mischaracterize the effects: floating isn’t a sealant finish and troweling doesn’t add air voids; it actually reduces voids and increases density.