The truss screed, like the roller screed, is capable of screeding a wide area--up to 65 feet. Thanks to the truss design that stabilizes it, it can span wide areas without twisting or torque. It can also have a vibratory action that helps to compact the concrete as you screed it. The truss screed can come with self-propelled winches that can, as Southern Tool states, "save labor."
A roller screed can be 6 to 43 feet long and has the form of a long, seamless pipe. Like a hand screed, it rests on the concrete form as it's dragged across the concrete. However, like a mechanical screed, it also has a motor which causes the roller to revolve in the opposite direction than its being pulled. Like a vibrator, the roller screed compacts the concrete as it revolves. This screed can also be used on inclined surfaces.
In some cases this screed can be applied to garage floors or outside areas where suitable. After application this screed is brought to a shine with a power float and pan. This leaves a super smooth top which prevents abrasion and corrosion that can be sealed or painted. In areas where this is not strong enough we lay concrete which is also brought to a very smooth finish.
The purpose of bull floating is to level ridges and fill voids left by the screeding operation. Drawing a bull float over the fresh concrete immediately after screeding is required to force down aggregate and raise cream (gravel-free concrete) near the surface for finishing. Bull float is used for areas too large to reach with a darby, though it may produce a wavier surface.
In hot weather, concrete might crack if joints are not cut within 6-12 hours after finishing screed. In this condition, we can early-entry dry-cut lightweight saws that can be used almost immediately after finishing instead of using a grooving tool to cut joints,. These saws cut 1" to 3" deep, depending on the model.