To make stucco for scratch coat, mix Portland cement, hydrated lime and sand. Mix the ingredients in a 5-gallon bucket or wheelbarrow with a hoe or other heavy pole, adding water until the slurry has the consistency of pudding. To add tooth, you can also mix a dash coat of sand, Portland cement and water to improve bonding with the stucco.
Using stucco requires applying at least three different coats – a scratch coat, a brown coat and a finishing coat. Depending on how much stucco you need to make for a scratch coat, choose a large container. If using a wheelbarrow, be sure to scrape and rinse it first. The formula to make stucco is one part Type 1 Portland cement, two to four parts sand, one-quarter part hydrated lime and enough water to make a slurry. For instance, if you start with 1 gallon of hydrated lime, you need to fill a gallon bucket with Portland cement and two to four buckets of sand.
To adjust the formula to make the brown coat, increase the amount of sand to three to five parts. To mix the finishing coat, follow the same formula as for the scratch or brown coat, using white Portland cement and oxide pigments (no more than 10 pounds of pigment per bag of cement). Write down the ratio you use so that the color of subsequent batches matches the first.