How to Mix Floor Screed

Kimberly Johnson

Floor screed is a mortar-like substance that installers spread in a thin layer onto the surface of a subfloor. After the screed is applied, installers place tiles, bricks and other types of flooring on top of it. The screed dries to a hard consistency, holding the flooring material securely in place.

Screed also applies to the long, thin board builders drag across the surface of the screed floor, making it smooth.

  1. Pour four parts of sand and one part of cement into a concrete mixer.

  2. Turn the mixer on and allow it to run for one to two minutes to thoroughly combine the dried substances.

  3. Place enough water into the mixture, using a garden hose, so that the mixture is damp but not wet. It's best to add only a little water at a time. To determine if the proper amount of water has been added, turn off the mixer and grab a handful of screed. Squeeze it tightly in your fist. Only one to two drops of water should come out of the mixture and it should retain a tight ball shape. If the screed crumbles, add a little more water. If too much water comes out, add more sand and cement.

  4. Tip

    Use a coarse concrete or builder's sand rather than fine mortar sand. If the layer of poured screen will be more than 2 inches thick, substitute concrete for the cement.