Specification

ManualsBrandsSHEETROCK Brand ManualsBuilding materialsUltraLight Imperial 1/2 in. x 4 ft. x 8 ft. Gypsum Base Board

Submittal Sheet

USG SHEETROCK

BRAND

Ultralight

gypsUm Base imperial

• The lightest 1/2" gypsum base for veneer plaster available

• Easier to lift, carry and install

• Special multi-layered laminated face paper to control water absorption, provide maximum

plaster bond, and resist sag

USG Sheetrock® Brand UltraLight Gypsum Base Imperial® is a re-engineered, lightweight gypsum

panel with a high strength-to-weight ratio composite design. The noncombustible, lightweight

gypsum core is encased in 100% recycled paper. The distinctive blue face paper is ideally

engineered for the application of veneer plaster, i.e., it controls water absorption, provides for

a strong plaster bond, and resists plaster slide. The panels provide a rigid base that resists sag.

When securely attached, the lightweight gypsum base adds lateral stability to the assembly. Also,

gypsum base partitions faced with gypsum plaster on both sides have high resistance to sound

transmission. Resilient attachment further improves ratings.

USG Sheetrock® UltraLight Gypsum Base Imperial is designed to be used with the following plaster

products: USG Imperial® Brand Veneer Finish, USG Diamond® Brand Veneer Finish, USG Apex®

Brand Veneer Finish, USG Norfolk Special Veneer Finish, USG Imperial Veneer Basecoat and USG

Diamond Veneer Basecoat.

1. USG Sheetrock® UltraLight Gypsum Base Imperial should only be used with veneer plaster

products.

2. USG Sheetrock® UltraLight Gypsum Base Imperial should not be used in areas exposed to

excessive moisture or as a base for adhesive application of ceramic tile (USG Sheetrock® Gypsum

Panels Mold Tough® or USG Durock® Brand cement board are recommended for this use).

3. Do not apply Diamond veneer ﬁnish, or any lime containing ﬁnish plaster to USG Imperial

gypsum base that has faded from exposure to sunlight. Where fading has occurred, treat

surface with either USG™ Plaster Bonder or a spray-applied solution of USG™ Accelerator-Alum

Catalyst before application of ﬁnish.

4. Gypsum base surfaces should be isolated with control joints or other means where: (a) Partition

or furring abuts a structural element (except ﬂoor) or dissimilar wall or ceiling; (b) Ceiling abuts

a structural element, dissimilar wall or partition, or other vertical penetration; (c) Construction

changes within the plane of the partition or ceiling; (d) Partitions or furring run exceeds 30'; (e)

Ceiling dimensions exceed 30' without relief, or 50' with relief; (f) Expansion or control joints

occur in the base exterior wall. Ceiling-height door frames may be used as control joints, as may

door frames that are less than ceiling height, if control joints extend to ceiling from both corners.

5. Must be stored o the ground and under cover. Avoid exposure to excessive, repetitive

or continues moisture before, during and after installation. Eliminate sources of moisture

immediately.

6. Avoid direct sunlight and temperatures exceeding 125°F (52°C).

7. Do not exceed the maximum spacing of framing members shown in the table below:

Maximum spacing of framing members for new construction:

Panel Thickness Base and ﬁnish assembly Framing spacing

(1)

in. mm in. mm

1/2 12.7 Imperial gypsum base one layer, 1-coat system 16 406.4

one layer, 2-coat system 16 or 24

(2)

406.4 or 609.6

(2)

two layer, 1 & 2-coat system 24 609.6

(1) For perpendicular or parallel application to framing. Perpendicular is preferred for maximum strength; parallel application

is not recommended for ceilings.

(2) 24" (609.6 mm) spacing requires joint treatment with USG Sheetrock® joint tape and USG Sheetrock® setting-type joint

compound (Durabond® or Easy Sand™)

LIGHTWEIGHT, RIGID GYPSUM BASE

FOR ECONOMICAL APPLICATION OF

VENEER PLASTERS

DESCRIPTION

LIMITATIONS

Summary of content (3 pages)

PAGE 1
Submittal Sheet USG SHEETROCK® Brand UltraLight Gypsum Base Imperial® Lightweight, rigid gypsum base for economical application of veneer plasters • The lightest 1/2" gypsum base for veneer plaster available • Easier to lift, carry and install • Special multi-layered laminated face paper to control water absorption, provide maximum plaster bond, and resist sag DESCRIPTION USG Sheetrock® Brand UltraLight Gypsum Base Imperial® is a re-engineered, lightweight gypsum panel with a high strength-to-weight ra
PAGE 2
Preparation Protect the product from moisture during storage and on the job. In cold weather, heat the interior of the building to a minimum of 55 °F (13 °C) for an adequate period before the application of plaster, while basecoat and finish is being applied, and until the finish is dry. Air circulation should be kept at a minimum level during this period. Warning: Store all USG Sheetrock® UltraLight Gypsum Base Imperial flat. Panels can fall over, causing serious injury or death.
PAGE 3
Installation Acoustical Sealant: Seal edges of gypsum base around entire perimeter of partition. Also, seal Finishing and Decorating See USG Diamond® Brand Finish Plaster submittal sheet P777 or USG Imperial® Brand Finish Plaster submittal sheet P775 on usg.com for finishing and decorating instructions. Product Data Thickness, in. (mm) 1/2" (12.7) Lengths, ft. (mm) 8 – 12 (2438–3658) Widths1, ft., (mm2) 48" (1218) or 54" (1370) Weight2, nominal, lbs./sq. ft., (Kg /m2) 1.25 – 1.35 (6.10 – 6.