Tools and Materials:
Paints: for base coat, a warm white flat latex paint;for stones, a warm white flat latex paint tinted with taupe and beige universal tints or artist's acrylics to achieve the stone color
Ladder, as needed
Paint roller and pan
Retractable measuring tape
1/4-inch-wide painter's masking tape
Razor blade or utility knife
Paint bucket and tray
3-inch-wide decorator brush
Wide broad knife
#6 artist's brush
Bucket of clean water
1) Determine the Size of the Blocks of Stone First, determine the size of your blocks of stone (usually rectangular — twice wide as high — but this can vary to suit your space). Remember to add mortar space between the blocks when figuring their size. Plan the total layout on graph paper, staggering the rows so that each block ends at the centers of those just above and below it.
2) Apply Base Coat Using a paint roller and pan, paint the wall with a base coat of warm white flat latex paint, and then allow it to dry thoroughly.
3) Draw Blocks onto Surface Start at a top corner of the wall, using your layout as a guide. Measure down from the ceiling to the point where the first two courses of block will meet, and lightly mark this point with a pencil. Do the same in the opposite corner. Using a chalk line, snap a guideline between the two marks, and lightly pencil (or chalk) in this horizontal line along the entire wall. Because most walls are not truly level, you'll have to make the blocks appear level with the ceiling, not the floor; any deviation, no matter how slight, will be more obvious at the ceiling line than the floor line. Using this first horizontal line as a reference, measure for and lightly pencil in the remaining horizontal lines; then define each block by drawing in the short vertical lines.
4) Create Mortar Lines To create the mortar lines, press narrow, 1/4-inch-wide painter's masking tape over the center of each marked line. Use a razor blade or utility knife to cut the vertical tapes, aligning them with the edges of the horizontal lines. The grid is now established
5) Paint the Stones Next, mix full-bodied flat latex paint with taupe and beige universal tints or artist's acrylics to the desired stone color, and pour a small amount into the paint tray. Seal the can, and set it aside to prevent spillage. Using a 3-inch-wide decorator brush, apply the paint. Pounce and twist the brush to create a stonelike texture. Vary the coloration from block to block by varying pressure on the brush.
6) Reveal Mortar LinesAllow the blocks to dry completely and then pull off the tape for the mortar lines by lifting the ends and pulling them toward you. You might be pleased with this look just as it is.However, for a more realistic representation, especially on exterior walls and interior ones that receive much sun, you should create shadow lines
7) Create Shadow Lines Decide on the sun's orientation — shadow lines will fall either along the right and bottom, or the left and bottom sides of the stones. Take the darkest color mixed into the stone paint, and thin it with water. Then, letting the edge of a broad knife be your guide, paint the shadow lines along the bottom of each stone and along either its left or right side (as determined, above) using an artist's #6 brush. When these lines are fully dry, dilute full-bodied white paint and then paint the mortar lines around the blocks. Leave the shadow lines untouched except for clipping their bottom corners.