Screeding is where you level the entire surface of a newly poured slab of concrete using nothing more than a level wooden plank and some manual labour, perhaps with a helper on larger surfaces. The key to success when you screed a concrete floor is in the timing of the process. You must screed while the concrete mix is still pliable, right after pouring. Wait too long and the concrete begins to harden; at this point, your screed will gouge the surface, destroying the finish of your slab.
Examine the 5 by 10 cm (2 by 4 inch) plank to make certain that the section you have is completely flat. Any bow or curve in the plank will translate into the concrete surface, creating curved surface. This plank will serve as your screed.
Cut the plank to a length that's the width of the concrete between the two forms at the sides of the slab plus an additional 30 cm (12 inches) with a saw. For ease of use, cut to fit the shortest slab edges.
Place the plank onto the forms on the two sides of the concrete slab. Rest the plank so it sits flat on the surface of the concrete starting at one edge of the slab, with 15 cm (6 inches) of plank on each side overlapping the forms.
With a helper holding the other end of the screed for longer slabs, drag the screed across the face of the concrete, using the forms as a guide to concrete surface level. Use a back and forth sawing motion to drag the screed, pushing excess concrete along the front of the wooden plank and leaving a level surface behind as the plank passes over the slab.
Check the surface as you screed. If the screed begins to gouge the surface, pull it back to a point before the gouging and advance it more slowly across the surface of the concrete.
Screed the entire slab from end to end, removing the excess concrete from the edge of the screed as you come to the end of the slab and disposing of it.
Hand screeding is effective only on slabs up to 9 m (30 feet) in width.