How to Mix Paints for Stucco

Place one part Portland cement, one part hydrated lime and three parts sand in a wheelbarrow. Add just enough water to make it into a thick, heavy paste before starting to apply a thin coat to the wall with a trowel. Apply this scratch coat so it’s no more than one-fourth of an inch thick, and be sure not to make up more of the scratch coat than you can apply in an hour because it dies quickly. You can add a little more water to the mix if needed – called retempering – but you should only do this once. After it is applied, leave it to dry.

Mix up the second, or brown, coat in the wheelbarrow, changing the proportions to one part Portland cement, one part hydrated lime and five parts sand. Add enough water to make a slightly more liquid paste than with the scratch coat. Apply it on top of the scratch coat, again making sure it’s only about one-fourth of an inch thick, and laying it on with wide sweeps. As it dries you can begin to texture it, but don’t mix up more than you can use in an hour because it dries quickly and can only be retempered once. Once applied, leave it to dry.

Make the finish coat from one part Portland cement, one part hydrated lime and two parts sand. Add water until the mix becomes a thick paste. Add one part mineral oxide pigment to the mixture in the color you desire. You can find this at a hardware store or paint store. You can’t use regular paint in stucco, but the pigments are available in a wide range of colors. Mix thoroughly with a heavy stick to ensure the color is evenly distributed. Apply it with the trowel over the previous coats of stucco, allowing for a slightly thicker coat – generally about one-half inch – to give complete cover and depth to the color. Leave it to dry.