Stucco can be tinted with a variety of colors to add depth.
Though wood is a time-honored choice for home exteriors, stucco has several advantages. It requires no painting since color can be integrated into the material. It is non-combustible since it is made of fire-retardant materials. It is also weather-resistant and maintenance free. It requires the correct proportions of sand for the best durability.
Basics
Stucco, sometimes called Portland cement plaster is generally made out of Portland cement, sand and water. Hydrated lime is also needed so the plaster is easy to spread and sticks to lath on walls. To minimize the number of ingredients, contractors can use plastic cement. This eliminates the need for lime, since plastic cement is workable as formulated. Most plasterers prefer the latter formulation, though a few mix equal parts of plastic and regular cement, and some use regular cement, especially when trying to match older stucco on a vintage home.
Types of Sand
Plasterers can use three types of sand from a home center or dry material yard. First is concrete sand. Its coarseness makes good quality plaster but is hard to spread. Second is masonry sand, which is too fine for use in base stucco coats because it can produce cracks in the plaster. Third is plaster sand, which allows spreadability but is coarse enough to avoid cracking. It must be clean and correctly graded. When delivered to the home site, it requires protection from dirt, oil, grease, leaves and debris.
Recipes
The actual sand required by stucco depends on use. For mixtures with Portland cement, the recipe for the first or scratch coat is the thickest. It requires one 94-pound bag of cement, 0.33 16-pound bags of type-S hydrated lime and 4 cubic feet of loose, damp plaster sand, which is equivalent to 5.33 5-gallon buckets. The secondary brown coat requires 10 percent more hyrdrated lime and sand. The finish coat needs one 94-pound bag of white Portland cement, 0.5 25-pound bags of type S hydrated lime and 5 cubic feet of loose damp plaster sand, which equals 6.67 5-gallon buckets. Any coloring is usually added to this finish coat.
Mixing
Plasterers generally start by pouring some water into the mixer and then part of the sand. Then come one or two bags of cement, depending on the size of the mixing machine, followed by the lime. More water is needed, and then the rest of the sand, followed by water to keep the mix workable. Workers must carefully gauge the amount of water needed because too much can weaken the stucco and form cracks. Mixers should stir the plaster for at least four or five minutes to allow the air bubbles to make the concrete flow. Lime introduces air entrainment into Portland cement. For plastic cement, the air entrainment agent is part of the mix.
Related posts
Stucco finishes are durable and beautiful.Portland cement stucco (also called Portland cement plaster) is a versatile finish material for both indoor and outdoor applications in wet, dry, cold and...
Stucco is a kind of exterior plaster made with concrete.Stucco is a kind of plaster used on building exteriors. Instead of the gypsum or lime used in most interior plasters, stucco is made with ce...
StuccoUsually people just buy ready-mixed stucco, but you can certainly make your own. With just a few materials, you can make a batch of stucco to use for your backyard project. Make sure you get...
Exterior stucco can last for decades.Stucco is one of the most durable, and most forgiving, of exterior coats for construction. The combination of cement, lime, sand and water creates a sturdy out...
Stucco adds distinctive texture and color to your home whether applied inside or out.Stucco, also known as Portland cement plaster, is an interior and exterior finish composed of sand, water and c...
