Things You Will Need
While stucco can be applied directly to many surfaces, for maximum durability a specially designed backer board is usually installed against the existing wall.
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Measure and cut backer board to fit the application. Score the backer board with the utility knife, place the scored line on a hard, straight-edge surface, such as the edge of a board, and push to snap off. Finish cutting the paper backing with the knife.
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Attach the backer board with backer-board screws and a power screwdriver. For exterior walls, install backer board over foam-sheet insulation. Make certain the screws go at least ½ inch into the wall, past the board and sheet insulation.
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Apply a cement bonding agent to the backer board and allow to dry according to the manufacturer's instructions.
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Mix the stucco according to the manufacturer's instructions and apply a primary “scratch” coat with a trowel. Work in a straight line, one wall at a time, to minimize lines. Allow it to harden slightly and finish by smoothing with a plasterer’s rake. Allow the scratch coat to cure for 48 hours.
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Dampen the scratch coat and apply final ¼-inch-thick finish coat with the finishing trowel. Texture as desired with a brush, sponge or trowel. Allow at least six weeks before painting.