Types of Gypsum Plaster, Kinds of gypsum plaster

Types of gypsum plaster speaks to types of gypsum plaster and explain gypsum plaster.

How they are manufactured in accordance with ASTM C28 and fall into two general categories.

The two categories are based coat plasters used for the underlying preparatory coats of plaster application finish coat plasters. Base coat plasters are provided either mill mixed, also called ready mixed, with aggregate added at the manufacturing plant, or neat, for use with aggregate added at the job site.

Common base board plasters:

Ordinary gypsum plaster, in various formulations suitable for either hand or machine application.

Wood fibered gypsum plaster, gypsum plaster blended with chopped wood fibers for lighter eight and greater strength and fire resistance.

Lightweight gypsum plaster, with perlite or vermiculite aggregate, for lighter weight and greater fire resistance.

High strength base coat plaster for use under high strength finish coats.

Finish coat plasters:

These are typically a blend of gypsum plaster and lime. The lime provides superior workability and finishing qualities, while the gypsum provides greater hardness and strength and prevents shrinkage cracking.

Ready mix finish plaster with factory blended lime and other ingredients.

Gauging plaster is gypsum plaster for job site mixing with hydrated which means prewetted on job site, finishing lime which is also called lime putty.

High strength gauging plaster which is formulated to produce a finish plaster with higher compressive strength.

Keenes cement is a proprietary gauging plaster that produces an exceptionally dense, crack resistant, low absorbency finish.

Molding plaster is a fast setting, fine textured material for molding plaster ornament and running cornices.


Retarders and accelerators can also be added to plaster mixers on the job site to adjust the setting time to job site temperature and humidity conditions.

Portland cement lime plaster, also known as stucco, is similar to masonry mortar. It is used where the plaster is likely to be subjected to moisture, as on exterior wall surfaces, or in commercial kitchens, industrial plants and shower rooms.

Because freshly mixed stucco is not as buttery and smooth as gypsum and lime plasters, it is not as easy to apply and finish. It shrinks slightly during curing, soit should be installed with frequent control joints to regulate cracking.

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