Twelve-foot module to reduce butt joints on compatible plaster layouts
Key features
Blue face paper for controlled absorption and plaster bond per USG
UltraLight positioning for rigid gypsum base per USG product literature
Technical specifications
| R-Value | 0.45 |
|---|---|
| Thickness | 0.5 in |
| Width | 48.0 in |
| Length | 144.0 in |
| Coverage | 48.0 sq ft/pack |
| Material | Noncombustible gypsum core with specialized blue face paper for veneer plaster applications per USG Imperial Base |
| Fire rating | UL classification as to surface-burning characteristics and noncombustibility per USG; core is noncombustible gypsum per typical listings |
| Sound rating | Acoustic performance is assembly-dependent; gypsum finish layers contribute to STC in tested partition assemblies (ASTM E90). |
| Density | Nominal 1.25–1.35 lb/sq ft per USG; planning calculation uses 1.25 lb/sq ft unless job submittal states otherwise |
| Construction type | ASTM C1396 1/2 in. gypsum base for veneer plaster per USG |
| Application area | Veneer plaster base on tall interior walls and ceilings when Imperial gypsum base is specified; coordinate plaster contractor sequencing |
Product details
Tall plaster substrates benefit from twelve-foot gypsum base when lifts allow—horizontal joints mid-elevation are the first places plaster telegraphs movement, so longer modules can improve the visual plane on stair towers and atrium walls.
This Imperial base covers forty-eight square feet; at the 1.25 lb per square foot planning factor used in YEARS, nominal sheet weight is near sixty pounds—still within UltraLight positioning versus many traditional bases per USG marketing.
Technical documentation mirrors the shorter module: ASTM C1396 gypsum base category, UL classification, GREENGUARD Gold, and Moisture Resistance: No on USG tables—select Mold Tough or other systems when humidity resistance is specified.
Confirm pricing with your supplier; YEARS may scale from eight-foot reference numbers—live quotes govern purchase orders.
Protect long edges; plaster bases are less forgiving than paint-grade drywall when corners are crushed during delivery.
Documents & certifications
Technical data sheet
Manufacturer-tested R-value, coverage, fire notes, and handling—use for submittals, RFIs, and field QA.
Download PDF (opens in new tab)Certifications & compliance
GREENGUARD Gold; UL classification per USG; ASTM C1396 gypsum base for veneer plaster
Frequently asked questions
Do plaster bases need different fasteners?
Do plaster bases need different fasteners?
Follow USG veneer plaster system guides for fastener type, spacing, and screw set below plaster surfacer—do not assume drywall screw schedules.
Can I store Imperial base outside?
Can I store Imperial base outside?
Keep gypsum panels dry and off the ground per GA-801 and USG handling literature; wet blue face paper can ruin plaster bond.
Is UltraLight Imperial the same as UltraLight drywall?
Is UltraLight Imperial the same as UltraLight drywall?
Different face paper and intended system: Imperial targets veneer plaster bases per ASTM C1396 categories, not generic painted drywall.
What coverage per sheet?
What coverage per sheet?
This 4x12 module covers 48 sq ft; divide net plaster substrate area by 48 and add waste for corners, beams, and patch-outs.