In order to choose the best stucco mix, decide whether you want a three coat or a one coat stucco, determine which coat you are applying, and decide if you want any additions to the stucco finish. Traditional stucco mix is applied in three coats, but there are also one coat mixtures available. If you use a traditional three coat application, be sure that you know which mix to use for the coat you are applying, as each one is slightly different. Once the basics of your stucco application are decided on, you can choose to add ingredients to the mix to achieve a variety of results.
Traditional stucco mix is comprised of Portland cement, hydrated lime, and sand. Newer one-coat mixes contain acrylic fibers and various chemicals, so that one mixture can be used for the entire stucco application. One coat mixes still require the application of multiple layers, but the simplified mix can make the entire process a little easier. Consider whether you are willing to mix separate batches of stucco mix for the different layers or if a one-coat option will work better for you. Remember that one-coat stucco mixes will still require several layers to achieve the proper thickness, but the same mix can be used for all of those layers.
If you choose to go with a mix that is made for the traditional three-coat application, the most important thing to remember is to get the correct ratio of ingredients for the coat you are working on. Stucco application should begin with a scratch coat that consists of one part Portland cement, one part hydrated lime, and two and a half to four parts sand. This layer forms the base layer of the stucco and bonds to the stucco mesh or lath that should be installed on the building. Make sure that the mix you use for this layer is intended to form the base layer of the stucco.
The next layer is the brown coat, which should have the highest concentration of sand in a three-coat application. Some contractors have been known to skip this layer, but if you would like to include it, there are mixes on the market that are specifically made for the brown coat. The stucco installation is completed with the finish coat. This mix should have the least amount of sand so that it will have a smooth finish.
Various ingredients can be added to the finish coat of the stucco mix to create different effects. Some mixes add acrylic fibers that add strength and flexibility to the stucco but also allow for textures to be created. Some common stucco textures are marble, adobe, and swirl, and pre-made mixes that allow you to create these textures can often be found in hardware stores. Pigment can also be added to the stucco mix during the finish coat to create different colors of stucco. If this is something you would like, look for a finish coat mix that has pigment in it or can have pigment added to it.