What type of cements can be used to make stucco?
There are many types of hydraulic cements that can be used as a binder for stucco, or portland cement plaster. The cement standards used in the United States most often are from the American Society for Testing and Materials (ASTM).
A hydraulic cement is one that sets and hardens when mixed with water. Cement, along with sand and water, are the basic ingredients of a plaster mix.
The following materials are candidate binders for stucco:
- Portland Cement, ASTM C150
- Blended Cement, ASTM C595
- Hydraulic Cement, ASTM C1157
- Masonry Cement, ASTM C91
- Plastic Cement/Stucco Cement, ASTM C1328 (primarily available in the west and southwest United States)
Hydrated limes, either ASTM C206 Finishing Hydrated Lime or C207 Hydrated Lime for Masonry Purposes, are also used with portland cement to provide workability. Hydrated lime may be used with blended cement or hydraulic cement, too, but is not used with masonry cement, mortar cement, plastic, or stucco cement. Those materials already contain workability agents and the addition of lime is neither necessary nor allowed. If used with those materials, lime poses potential problems such as reduced strength or durability.
White cements are also available for use in stucco. They are generally specified under C150, C91, or C1328. Specifying white cement – sometimes white cements are blended with pigment in the factory or on the job to create colored mixes. Where white or colored plaster mixes are used, they often are applied only as the finish coat.
Standards for all of these materials are available from ASTM.