Still UltraLight-class handling versus many traditional moisture boards at similar thickness
Key features
Moisture-resistant core with moisture- and mold-resistant recycled papers
ASTM D3273 mold-surface testing and ASTM C1396 water-resistant board categories per USG
Technical specifications
| R-Value | 0.45 |
|---|---|
| Thickness | 0.5 in |
| Width | 48.0 in |
| Length | 96.0 in |
| Coverage | 32.0 sq ft/pack |
| Material | Moisture-resistant gypsum core with moisture- and mold-resistant recycled papers (UltraLight Mold Tough per USG) |
| Fire rating | Noncombustible gypsum core per typical gypsum-board listings; UL classification for surface-burning characteristics and noncombustibility per USG. Not a Type X (firecode) panel unless a separate Type X SKU is specified—verify UL design listings for rated assemblies. |
| Sound rating | Acoustic performance is assembly-dependent; gypsum finish layers contribute to STC in tested partition assemblies (ASTM E90). |
| Density | Nominal 1.35 lb/sq ft panel weight per USG Mold Tough UltraLight specifications |
| Construction type | ASTM C1396 for 1/2 in. water-resistant gypsum wallboard and 1/2 in. exterior gypsum soffit board categories per USG Mold Tough UltraLight listings |
| Application area | Interior walls and ceilings where enhanced moisture and mold resistance is desired—bath, laundry, and similar areas per typical use; follow USG installation and finishing guidance |
Product details
Bath, laundry, and utility spaces expose gypsum to humidity spikes and surface wetting that standard paper can’t tolerate; the wrong board layer invites softening, mold anxiety, and expensive rip-out even when the tile system above is correct.
UltraLight Mold Tough combines USG’s lighter 1.35 lb per square foot nominal weight class with a moisture-resistant core and green/brown mold- and moisture-resistant papers—about forty-three pounds nominal on a four-by-eight sheet for handling estimates.
USG cites ASTM C1396 for water-resistant gypsum wallboard categories and references ASTM D3273 mold-surface testing in its literature, alongside UL surface-burning classification language and GREENGUARD Gold for indoor emissions documentation.
Mold Tough is a system decision, not a magic barrier: membranes, pan flashing, sealants, and often cementitious backers still govern true wet walls; coordinate TCNA details, USG instructions, and the AHJ before deleting cement board from a shower package.
For fire-rated or sound-rated partitions, read the panel edge type and UL file—this line is not automatically Type X and must not substitute Firecode assemblies without an explicit listing match.
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 (surface burning / noncombustibility per USG); ASTM C1396; ASTM D3273 mold-surface test per USG
Frequently asked questions
What makes Mold Tough different from standard UltraLight?
What makes Mold Tough different from standard UltraLight?
UltraLight Mold Tough uses a moisture-resistant gypsum core and moisture-/mold-resistant papers; USG states ASTM D3273 chamber testing and ASTM C1396 compliance for the water-resistant board categories listed on its product page.
Can I skip cement board in a wet wall?
Can I skip cement board in a wet wall?
That is an assembly and code decision. Mold Tough is marketed for enhanced moisture/mold resistance, but showers and tub surrounds often still require systems listed for wet areas—confirm with USG details, TCNA guidance, and your AHJ.
Is this panel Type X?
Is this panel Type X?
Not automatically. For fire-resistance-rated assemblies, use the exact board type and UL assembly referenced in the design. Do not substitute Mold Tough UltraLight for Type X unless the listing explicitly allows it.
What weight should crews plan for?
What weight should crews plan for?
USG lists nominal 1.35 lb/sq ft for UltraLight Mold Tough 1/2 in. Multiply by sheet area for nominal pounds before lifts and stocking.