Screeding
Also called: screed, strike off, striking off concrete
Striking off freshly placed concrete to the level of the forms by drawing a straight board across their tops with a sawing motion. It sets the slab's thickness and slope; floating and troweling only smooth what screeding left.
The screed is usually a straight 2×4 a foot or two longer than the slab is wide, or an aluminum screed bar. Two people hold it on the form tops, tilt it slightly forward, and pull it toward them while sliding it side to side. Concrete builds up in front of it; a third person rakes the surplus ahead and fills any low spots that show behind. A second pass catches what the first missed. On a slab too wide to span, a temporary screed rail or pipe is set at grade in the middle and pulled out afterward.
Screeding happens as the concrete is placed, not after — a ready-mix pour is placed and screeded a few feet at a time from the far corner back toward the truck. The forms have to be straight, level to the planned slope and firmly staked, because the screed copies whatever they do. That’s why the guide spends more time on forms than on finishing.
After screeding comes the bull float, then a wait for bleed water to evaporate, then edging, jointing and the broom.