DIAMOND® Veneer Basecoat

Yes. Mill-mixed RED TOP® Brand Finish Plaster or other jobsite lime/gauging plasters can be applied over Veneer Basecoats.

IMPERIAL® Brand Finish Plaster is the stronger and more abrasion resistant. DIAMOND Interior Finish Plaster is designed for ease of use and slightly improved abrasion resistance when compared to gypsum panels.

SHEETROCK® Brand Wallcovering Primer (or equivalent) should be used to prime a veneer plaster surface. Lime containing veneer plasters (such as DIAMOND® Interior Finish) should be treated with an alkaline resistant paint (pH greater than 12).

A Conventional Plaster system can be painted after it is completely dry.

Yes, but only on open throat doorframes, per door manufactures requirements. RED TOP ® Gypsum Plaster mixed with sand (1 part Red Top Gypsum/ 2 parts sand per bag recommendation) is most commonly used for full grouts. See Page 281 Gypsum Construction Handbook for full details.

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.

Yes. If the main tees, cross tees and hanger wires are properly sized and spaced to carry the plaster load and only RED TOP® STRUCTOBASE gypsum basecoat plaster is used for the scratch and brown coats.

RED TOP® STRUCTOBASE gypsum basecoat 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).

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.

No. An alum spray must be applied prior to application.

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.

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.

Do not exceed 16 inches on center.

When installing a veneer plaster system it should be designed at deflection L/240 and L/360 for a Conventional Plaster system.

When installing a veneer plaster system it should be designed at deflection L/240 and L/360 for a Conventional 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.

Do not exceed 16 inches on center.

Determine if the plaster became contaminated after its removal from bag. First mix plaster from the storage bin in one mix. Then, under identical conditions, use plaster directly form the bag for a second mix. Any lumps of setup plaster in bags or storage bin should be removed. If both mixes set too fast and do not appear contaminated, the plaster may be at fault or either of the two following causes may be present: 1) Dirty mixing equipment or 2) Impurities in mixing water.

Large particles in plaster slurry settle out against the face of the mold. Mix until the plaster "creams". Slurry is then thick enough to prevent settling.

The pieces were probably not handled properly. Wet pieces have about half the strength of a dried piece making them vulnerable to abuse.

The pieces might be calcined (burnt) because of extremely high drying temperatures. Regulate temperature of dryer at about 120ºF and remove pieces as soon as they are dry.

The piece was not dried correctly.

The piece was not dried correctly.

The plaster was improperly soaked or mixed. Start with a[!]good quality plaster. Sift plaster into the water at one time. Let the plaster soak completely until all particles are wetted. Thoroughly mix with a mechanical mixer having the propeller adjusted so air is not whipped into the mix. Mixer should be set at a high speed (approx. 1,750 rpm). Air entrainment is a widespread problem and should be constantly guarded against. Always add plaster to water, never the reverse.

The plaster was not dried correctly.