INTEGRALLY COLORED FINISH (STUCCO)
Texture, as a description of surface appearance, is identified generally with the method and tools used to achieve the finish. Texture can be varied by the size and shape of the aggregate used, the equipment or tools employed, the consistency of the finish coat mix, the condition of the base to which it is applied, and by subsequent decorative or protective treatments. Factory-prepared, integrally colored finish coats is a design blend of natural color of the cementatious materials, aggregate, and any color pigment, and their proportions to each other. The amount of the pigment required depends on the color of the cement, the color of the fines in the sand, the color intensity desired, and the water content of the plaster.
The uniformity of color cannot be guaranteed by the material manufacturer of the component materials or by the applicator (contractor). Color 'uniformity is affected to an even greater degree by variations in thickness and differences in the suction of the base coat from one area or location to another, the type of finish selected, the migration of color pigments with moisture, and with the job site climatic and environmental conditions. These factors are rarely under the control of the applicator.
Color uniformity is dependent on batching uniformity and the use of consistent techniques in the application, finishing, and curing of the finish coat. Some color variation and diversity are generally under the control of the applicator and can usually be traced to one or more causes; including the following:
- Uniformity of proportioning;
- Inconsistency between batches;
- Thoroughness of mixing;
- Cleanliness of equipment;
- Application technique;
- Curing conditions and procedure;
- Cold joints in brown coat;
- Assorted surface conditions to base coat (troweled, scraped, darbied or rodded, wet and dry floated); and
- Inconsistency or excessive pre-damping of brown coat prior to applying color coat finish.
Color consistency and uniformity can ultimately be established when the applicator applies the integrally colored finish in a workmanlike manner, in accordance to stucco manufacturer's guidelines and industry standards. The finish coat should be applied with sufficient material and pressure to ensure tight contact with, and complete coverage of the base-coat and to recommended thickness to acquire the chosen finish. Color variation in exterior finish-coat stucco can be corrected by application of a fog coat. A fog coat should be applied to a dry surface, using as fine a spray as possible. This technique returns the loss colored pigment back to the original stucco finish. Curing of the fog coat is necessary under hot, dry, or windy conditions by applying a light fog spray of water the following day.