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Extend the set time of conventional, veneer and lime finish plasters and setting-type joint compounds.
Key Documents & Design Files
Main FeaturesGypsum Plaster Retarders extend the set time of conventional plasters, veneer plasters, lime finish plasters and setting-type joint compounds. By slowing the chemical crystal formation that causes gypsum plaster to set or harden, Gypsum Plaster Retarders allow more time to complete each job. Gypsum Plaster Retarders easily disperse into water prior to adding plaster and are available in the following formulations:
Installation Guide PDF 50.6 KB
Data Sheets & Specifications
|Data/Submittal Sheet (English)||PDF 870.4 KB|
Catalogs & Brochures
|System Catalog (English)||PDF 18.5 MB|
Installation & Technical Manuals
|Technical Guide (English)|
|Installation Guide (English)||PDF 50.6 KB|
SDS, Certifications & Reports
|SDS (Spanish)||PDF 184.9 KB|
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What is the recommended stud spacing for installing conventional plaster?
Do not exceed 16 inches on center.
Can conventional 3-coat plaster be used with drywall grid?
Yes. If the main tees, cross tees and hanger wires are properly sized and spaced to carry the plaster load and only Red Top®; Structo-base® gypsum basecoat plaster is used for the scratch and brown coats.
Can USG Veneer Plaster be applied directly over CMU?
The CMU must cure for at least 45 to 60 days prior to the plaster application. Refer to USG system folder SA920 for specific application directions.
When can veneer plaster be painted?
Veneer plaster can be painted when it is completely dry. The best way to determine if the plaster is dry is by taping a piece of 12" by 12" plastic to the surface. If any moisture remains on the plastic after 24 hours then the plaster is not completely dry.
What are the only base coat plasters that can be used as the scratch and brown coat for a conventional 3-coat application over wide-flange (1 inch or greater) framing?
USG has three products that can be used: Red Top® Gypsum Plaster, Red Top® Wood-Fiber Gypsum and USG® Structo-Base® Gypsum Plaster.
Can plaster be used for grouting doorframes?
Yes, but only on open throat doorframes, per door manufactures requirements. Red Top® Gypsum Plaster mixed with sand is most commonly used for full grouts. (Recommendation: 1-part Red Top Gypsum/ 2-parts sand per bag)
See the Gypsum Construction Handbook for full details.
When can a conventional plaster system be painted?
A conventional plaster system can be painted after it is completely dry.
What is the shelf life of plaster?
Plaster can be stored 3-6 months if it is stored in a cool, dry place, protected from extreme heat and cold, direct sunlight and at a temperature above 45°F (7°C).
What is the best way of repairing an old wood lath plaster application?
Remove the old plaster down to the wood lath, staple metal over the existing lath and apply Red Top® sanded conventional basecoat over the metal lath. Any USG finish plaster can be applied over the basecoat plaster for a final coat.
What paints are recommended for decorating veneer plaster?
Consult paint manufacture for proper primer selection for both lime-containing finish plasters, such as Diamond® Veneer Finish; or non-lime-containing finish plasters such as Imperial® Veneer Finish. See literature piece PM15 for Preperation for Painting details.
Can Veneer Plaster be applied to sun-faded USG Imperial® Brand Gypsum Base?
No. An alum spray must be applied prior to application.
What are the deflection design criteria for installing plaster systems?
When installing a veneer plaster system it should be designed at deflection L/240 and L/360 for a Conventional Plaster system.
What is the difference between USG Imperial® Veneer Finish Plaster and USG Diamond® Veneer Finish Plaster?
USG Imperial® Veneer Finish Plaster is stronger and more abrasion resistant.
USG Diamond® Veneer Finish Plaster is designed for ease of use and slightly improved abrasion resistance when compared to gypsum panels.
What is the recommended spacing of control joints for a plaster system?
Control joints are not to exceed 30 feet for walls and ceilings. The spacing for a ceiling with perimeter relief is not to exceed 50 feet.
Can USG Red Top® Brand Finish Plaster be applied over Veneer Basecoats?
Yes. Mill-mixed USG Red Top® Brand Finish Plaster or other job-site lime/gauging plasters can be applied over Veneer Basecoats.