Materials required: Portland Cement, mortar sand/aggregate mix, RockMolds Integral Color, Rockmolds Min Trowel, Rockmolds Stone Powder Release, RockMolds Edging Stamp, RockMolds Stone Color Water Base Stains, RockMolds Stone Sealer.
1. Site prep: Spray out desired layout of edging with marking paint. Remove 2” of soil along all LF of painted area. Keep in mind the finished elevation of edging against all grades.
2. Install 20’ pieces of rebar in all LF of excavated trench. Bend as required to emulate the curves. Tie ends together with tie wire.
3. Mix the concrete. A rich mix (more cement) and small gravel (1/4” minus aggregate) is a good consistency for stamping. More cement with small gravel will provide a stampable consistency with greater strength.
Tip #1: Adding a RockMolds Integral Color into the mix is a good idea for the base color. In general, 4 scoops of cement to 16 scoops of sand with 1 cups of integral color is a great mix for concrete edging.
4. Deposit the concrete along the rebar in the trench with a round point shovel. Pull the rebar up into the center of the concrete as you deposit. The overall form should be 4-5” thick. In general, use mini scoops, careful not to overfill the trench, as you can always add more. During the summer months, be also careful not to deposit too much concrete into the trench ahead of the finish trowel man, as the longer the concrete sits untouched, the more difficult it will be to finish.
5. Trowel the concrete into the desired form, a 4”x4” square tube.
Tip #2: Use two Rockmolds Min Trowels, squaring off the sides and top as troweling. Smooth the concrete, while not over-troweling, to get ready to stamp.
6. Utilize the “thumb test” to see if the concrete is ready to stamp. Simply press your thumb onto the concrete, and if it does not sink in, while taking an impression of your thumb, the concrete is ready to stamp.
7. Lightly apply a Rockmolds Min Trowel to the concrete square tube, touching up any inconsistencies. Dust a Rockmolds Stone Powder Release onto the surface of the 4″ tube, to allow the stamps to leave an impression, without sticking to the concrete. Choose a Rockmolds Stone Powder Release, which will compliment the integral base color, such as a brown with a gray, a black with a brown, etc.
Tip #3: Make sure the releasing agent is shaken up and powdery before grabbing a small handful. Then apply it as if skipping a rock across the water.
8. Press in the RockMolds Edging Stamp onto the concrete. Use care to keep the form of the concrete tube a square as the stamp is pressed in. Match up the seam lines of the last sandstone impression, and continue to stamp.
9. Touch up (after the concrete has had a chance to firm up at least an hour) utilizing a margin trowel and chip brush. Clean the joints and shape between the stones, and brush out any obvious blemishes on the stone.
10. In most cases, on the following day after installation, the stones can be hosed off thoroughly, and allowed to dry.
11. Color the stones using RockMolds Stone Color Water Base Stains on the dried stones for additional coloring and highlights. With the integral color, release agent color, and now the highlights of the water-based stains, your stones will have a multitude of colors, as natural stone would. Allow to dry.
Tip #5: Start with a light color of the RockMolds Stone Color Water Base Stains, and then go darker. Think of this process of painting with watercolors, only on concrete. You can always add more layers of color.
12. Spray on a light coat of RockMolds Stone Sealer to preserve the color. Sealant may be applied every year after that, like any other decorative concrete, to preserve the color.