Systems and methods according to present principles enhance aspects of applied plaster coats. In particular, the materials include a synthetic substitute aggregate (SSA), added to a cementitious base coat, for a plastering step prior to application of stucco or acrylic synthetic finishes or finish coats. The addition of SSA to a pre-blended cementitious base coat creates a light weight product which in some implementations is highly advantageous for the plastering industry.