Wet (hydro) blasting and sand blasting may be necessary to prepare the surface prior to the application of any stucco materials. Hydro Blasting and Sandblasting are general terms to describe the act of removing fine bits of material at high-velocity to clean a surface. Silica sand is the most commonly used material for sandblasting, but any small, relatively uniform particles will work.
When applying stucco, one does not want to trap dust, dirt, or bubbles in a previous layer of paint, or other imperfections under the new layer. By sandblasting, which is a technique of launching small bits of abrasive sand at the surface at a high speed, all imperfections are loosened and can then be easily washed off. Wet sandblasting means water is used in the technique to remove debris such as paint, tex-cote or old stucco, from a structure. This creates a smooth surface that is ready for a redesign with new stucco. Wet sandblasting is the most common sandblasting technique.