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U.S. Gypsum SecuRock 1/2 in. x 4 ft. x 8 ft. Glass-Mat Roof Board
Regular price $41.26Orders start at $399 — combine any items to reach the minimum. Learn more
U.S. Gypsum SecuRock 1/2 in. x 4 ft. x 8 ft. Glass-Mat Roof Board
This is a U.S. Gypsum SecuRock 1/2 in. glass-mat faced gypsum roof board in a 4 ft. x 8 ft. sheet, sold per piece. The gypsum core with fiberglass face provides a dimensionally stable substrate for low-slope roof membranes. Pair it with compatible membranes and adhesives per the roofing assembly specification.
Key Features:
- Glass-mat facing: Gypsum core with fiberglass face for moisture-resistant roof board performance.
- Broad approvals: UL Classified and FM Approved for use in listed roofing assemblies.
- ICC-ES report: Covered by ICC-ES ESR-3044 evaluation report.
- Fire and moisture tested: Meets ASTM E84, ASTM E136, ASTM D3273 mold resistance and ASTM E96 water vapor transmission standards.
- Full sheet format: Supplied as a 1/2 in. thick, 4 ft. x 8 ft. board per piece.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | U.S. Gypsum |
| Manufacturer model | 221851 |
| Sell unit | 1 board, 1/2 in. x 4 ft. x 8 ft. |
| Product line | SecuRock |
| Material | Gypsum with Fiberglass Face |
| Dimensions | 4 ft. x 8 ft., 1/2 in. thick |
| Approvals | ASTM D3273; ASTM E84; ASTM E136; ASTM C1177; ASTM E96; ICC ES-ESR 3044; UL Classified; FM Approved |
| Weight | 64 lb |
| Intended use | Glass-mat roof board substrate for low-slope roofing |
Coverage & How Much You Need:
One sheet covers 32 sq ft (4 ft. x 8 ft.). Divide the deck area by 32 sq ft and add cut waste to determine sheet count.
Fit and Compatibility:
Use as a substrate under single-ply, modified bitumen or other low-slope membranes per the assembly specification. Compatible fasteners/plates or approved adhesives are sold separately.
Frequently Asked Questions (FAQ):
Q: What is included in the sell unit?
A: One 1/2 in. x 4 ft. x 8 ft. SecuRock glass-mat roof board, sold per piece.
Q: How much does one board cover?
A: Each 4 ft. x 8 ft. sheet covers 32 square feet before waste allowance.
Q: How much does the sheet weigh?
A: The listed item weight is 64 lb per board.
Q: Is the board mold resistant?
A: It meets ASTM D3273, the standard test for mold resistance of interior surfaces, along with ASTM C1177 glass-mat gypsum requirements.
Q: What fastens this board to the deck?
A: Use the fasteners, plates or adhesives called out in the roof assembly specification; they are sold separately.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
SecuRock glass-mat roof board is the standard choice for cover board or thermal barrier work under single-ply and modified bitumen systems where an ICC-ES evaluated, UL/FM listed board is specified. Follow the membrane manufacturer's fastening pattern and allow for board edge gapping per USG instructions. For assemblies requiring a non-combustible cement substrate instead, use SecuRock cement board.
Gypsum boards are heavy and fragile at edges; carry sheets on edge with a partner and use proper lifting technique to avoid back strain and breakage.
Order U.S. Gypsum SecuRock 1/2 in. glass-mat roof board for a stable, approved roof substrate.
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