Read this before using stucco – Techniques, benefits, and more uncovered!
Stucco is a plaster or cement rendering covering on a wall or ceiling surface, often seen on exterior facades. Stucco is essentially troweled onto the surface in multiple layer application.
A photo of a thin stucco application directly on top of a vertical brick wall follows below. The left side of the image shows a thin stucco application on the vertical face of the brick and on the right-hand side of the photo you can see the red brick wall. Although the stucco application in the photo below is very thin it is actually a 2-coat application. The first code is approximately 7/16 of an inch thick, or roughly half of an inch. The second and final code of stucco is an extremely thin skim application.
The first coat is often called a scratch coat or brown coat. In a typical three coat system, the first coat will actually have a key, also called a scratch, applied to the surface. Professional applicators such as our company will actually use special tools designated or created to apply this scratch coat. A common version of this tool looks like a very large metal comb with a handle similar to a wide blade taping knife. The scratch tool is dragged across the surface of the surface of the freshly applied wet it scratch coat. This procedure will leave a rough texture. That rough texture essentially creates what we call a key. The key is a groove in the texture which allows a successive coat of application to be applied and have a greater surface area to which it can adhere, a non-planer texture. The key in the substrate allows be better cohesion and bond between the two coats of stucco.
A top coat of stucco, usually the final coat is often called a white coat. In in historic construction, the white coat was a finer blend of fired plaster, usually of fine aggregates and binders, and often white in color.