The screed was a straight board dragged across wet concrete to make it flat. Two men. One board. One on each end. They set the board on the forms and pulled it toward them in a sawing motion. Back and forth. The board rode on the forms like a rail and the wet concrete underneath the board got pushed and pulled into a flat plane. The excess concrete piled up in front of the board and the low spots filled in behind. The screed was the first pass at flat. Not smooth. Flat. Smooth came later. Flat came from the screed.

The board had to be straight. A crooked screed made a crooked slab. The finisher checked the board by sighting down the edge the way a carpenter checks a piece of lumber. If the board was bowed the finisher replaced it. A sixteenth of an inch of bow in the board became a sixteenth of an inch of wave in the concrete and the wave showed when the concrete dried and the light hit it wrong. The floor looked like water. The wave was permanent. The screed board was the cheapest tool on the pour and the most important tool on the pour because the screed board set the surface that everybody walked on.

The two men on the screed had to work together. If one man pulled faster than the other the board twisted and the concrete was uneven. The men found a rhythm. Pull and saw. Pull and saw. The rhythm was the coordination and the coordination was the flatness. Two men who had screeded together for years did not talk during the pull. They read each other through the board. The resistance in the board told each man what the other man was doing. The board was the communication. The concrete was the medium. The flat slab was the conversation between two men who did not need to speak.

Power screeds do the work now. A vibrating beam on a track. One man operates the controls and the beam rides the forms and vibrates the concrete flat. The power screed is faster and flatter. The power screed does not get tired. The two men with the board got tired and the tired men made waves in the afternoon that they did not make in the morning. The power screed makes the same surface at four o'clock that it makes at seven. The power screed does not have a rhythm. The power screed has a setting. The setting replaced the rhythm and the rhythm was the thing that made the two men a team.

See also: Bull Float, Aggregate