A popular method for adding a decorative finish to newly placed concrete is by using stencils. Stencils are patterns of brick, stone, tile or other finishes that use grout lines to create a pattern. A stencil is pretty much a pattern of grout lines.
The way they work is quite simple yet very innovative.
When a concrete slab is placed and leveled but still soft and workable a stencil can be laid out over the concrete and worked into its surface.
The stencil is usually 1/16” of an inch thick or so and when worked or bull floated it temporarily embeds itself into the soft concrete surface.
This leaves the area of concrete in between the stencil exposed. This exposed area is then broadcast with a surface colorant and then worked into the concrete, all the while the stencil is keeping the area under it free of color.
When the concrete hardens the stencil is removed from the surface, exposing the grey uncolored grout line beneath it.
This in turn creates a pattern similar in effect to brick, tile or grouted stone