Why Finishers Run a Jitterbug Over Fresh Concrete

The Problem

Concrete is mostly stone. Right after a pour, the big pieces of aggregate sit wherever they landed — including at the surface — and a float can only do so much when it's riding over rocks a half-inch down. The finish ends up rough, or the finisher fights the float trying to bury stones one at a time.

The Main Idea

The jitterbug (a concrete tamper) is a mesh or grid plate on a handle that gets pressed — not slammed — across the surface of fresh concrete:

1. Work the tamper over the pour while the concrete is still plastic, pressing straight down in overlapping placements.
2. The grid pushes the larger aggregate down below the surface while letting the sand-and-cement cream rise through.
3. Float and finish as normal. With the stone sitting lower, the float rides on cream and the surface closes up noticeably smoother.