Finishing the Slab

After being screeded, large slabs are flattened with a bull float. Bull-floating also pushes the coarse aggregate down and brings up the finer, more easily finished “cream.”

A magnesium float is used where a bull float is too large.

Edging is a multi­step process that’s repeated each time the slab is floated or troweled.

After edging and bull-floating or magging is done, the slab is allowed to sit. Excess, or “bleed,” water comes to the surface and evaporates.

Once the concrete loses the shine from the bleed water, it’s bull-floated or magged again.

When the slab is hard enough that a trowel won’t dig in, it’s steel troweled to compact the surface.

Knee boards (here made of rigid foam, but usually of plywood) keep workers from sinking in the center of a large slab.

A slab may be finished with a broom to provide traction.

Keep fresh concrete wet for at least 72 hours by covering it with plastic or wet burlap, or by continuously running a sprinkler.

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