Concrete Finishing Techniques
CSI Division 03, Concrete
The sequence of hand and power tool passes, screeding to level fresh concrete to the form height, bull floating to close the surface right after screeding, and then a final trowel finish for a smooth interior floor or a broom finish for a slip-resistant exterior surface, that turns a wet pour into a usable, finished slab.
Why it matters
Each pass has to happen at the right point in the concrete's curing window. Finishing too early pulls water and fine material to the surface, weakening it, while finishing too late means the concrete has already stiffened too much to work. Choosing the wrong final finish for the setting, a slick trowel finish on an exterior walkway, for instance, can also create a real safety hazard.
On a real project
A crew screeds a freshly poured interior slab level with the form boards, bull floats it to close the surface, and finishes with a steel trowel for a smooth, hard surface, while a separate exterior slab poured the same day gets a broom finish instead to provide slip resistance in wet weather.
Who this matters most to
A Concrete Worker times each finishing pass to the concrete's actual set, a skill that comes largely from experience rather than a fixed schedule, since set time changes with temperature and humidity.
Where this goes wrong
A crew applies a smooth trowel finish to an exterior walkway slab to match the interior floors nearby, without considering that the finish will be dangerously slick once it's wet. The mistake isn't caught until after the concrete has cured, and the surface has to be mechanically roughened afterward to make it safe.