To apply stucco to the exterior of a house, begin by prepping the exterior by applying a concrete bonding agent to any masonry or concrete wall. For wood exteriors, wrap the house in either plastic house wrap or roofing felt to protect the wood from moisture, and make sure to overlap vertical seams by 2 inches and horizontal seams by 6 inches. Then apply 17-gauge metal mesh over the wrap, and use galvanized roofing nails to secure it.
Wait for a cloudy day with temperatures between 55 and 80 degrees Fahrenheit to apply stucco to ensure that the exterior dries correctly. When applying the stucco, start with a scratch coat made of mortar mix and applied with a trowel. Press the mortar mix into any metal mesh to ensure proper adhesion. Let the scratch coat dry for two to three hours, and then use a scratch tool to make horizontal scratches on the surface that are 1/8 inch deep.
Let the scratch coat cure for several days, making sure to mist the surface of the stucco base with water to prevent the outside of the scratch coat from curing too quickly. Next, apply the brown coat with a trowel, making it perfectly smooth and 1/2 inch thick. Repeat the curing process before proceeding.
Apply the final stucco coat in a layer that is 1/4 inch thick. Use finishing tools, such as a wood float, trowel or sponge, to create the finished texture of the stucco exterior.