How to Scratch & Brown Stucco

Scratch and brown plaster coats are part of the three-step plaster process used in both interior and exterior applications. The scratch coat is applied as the base coat and is applied over concrete, lath or wire. This thick coat is notched so the second coat has ridges or keys to adhere to when it's applied. The brown coat can be left as the finish coat or a skim coat, a thin finishing coat, can be applied over it to create the final product.

Scratch Coat

Trowels are essential plastering tools.
  1. Mix your plaster according to the manufacturer's directions or use premixed plaster. Open the container and stir your plaster with a drill and a mixer paddle to ensure the plaster is of an even consistency.

  2. Pull a generous amount of plaster out of the bucket and apply it to your trowel.

  3. Trowel a thick coating of plaster onto the wall. The thicker you can make this coat of plaster, the stronger the wall will be when completed. The thickness you achieve is determined by how much plaster you can put on the wall without its falling off because of its own weight.

  4. Scratch the surface of the plaster with a notched trowel. Hold the trowel staight, not at an angle, and drag it horizontally across the plaster, creating shallow scratches in the surface. These scratches are what the next coat of plaster will adhere to. Allow the scratch coat to cure or dry before applying the brown coat of plaster.

Brown Coat

  1. Mix the plaster according to your manufacturer's directions or use premixed plaster. Mix the plaster with a drill and mixer paddles to make sure the plaster is the same consistency throughout.

  2. Pick up a generous amount of plaster and apply it to your trowel.

  3. Smooth the plaster over the wall with your trowel, filling the notches of the scratch coat. Plaster the entire surface, creating a smooth and even surface.

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