Does stucco require curing?
For cement-based materials, curing is defined as maintaining an appropriate temperature and moisture content for a specific period of time during the early life of the material. All traditional portland cement-based materials, such as stucco, require curing.
Sun and wind, alone or in combination, drive moisture out of fresh stucco. To be applied to a wall, stucco must be wet enough to be troweled, and floated, but not too wet that it sags or won’t stick. Base coats, of which there may be one or two (sometimes scratch and brown are combined), can be wetted once they have developed adequate strength so that they are not washed away by the water. Since the coats are thin, they can’t hold as much moisture as is ideal for curing—especially if they are competing with sun or wind, which both cause evaporation.
The first two days are the most critical period. The entire first week is important, however, so it is a common recommendation that the base coat stucco be misted or fogged periodically for the first three to seven days after application. If the relative humidity of the air is greater than 70 percent, moist curing may be accomplished without additional wetting of the surface.