DensDeck Prime 1/4 in. Primed Roof Board 4 ft. x 8 ft. Sheet (Cover Board)
DensDeck Prime 1/4 in. Primed Roof Board 4 ft. x 8 ft. Sheet (Cover Board)
Primed gypsum roof cover board sheet
DensDeck Prime is a primed gypsum roof board designed to provide a durable, high-performance cover board surface for commercial roofing assemblies. It features a fiberglass mat facer and high-density gypsum core to help improve membrane bond strength while supporting fire and moisture resistance requirements in many systems.
Key Features:
- Enhanced Adhesion Surface: Coated fiberglass facer is designed to provide improved compatibility and performance with roofing adhesives in fully adhered systems.
- Fire-Resistant Cover Board: Noncombustible gypsum roof board with 0/0 flame spread and smoke developed when tested per ASTM E84; referenced as FM Class 1/UL Class A performance for assemblies.
- Moisture-Resistant Performance: Designed for water resistance with up to 5% water absorption by weight and 1-gram nominal surface water absorption on both sides.
- System Versatility: Created for mechanically fastened, adhered, and partially adhered roofing systems.
- Durable Protection Layer: Helps defend roof assemblies from punctures, wind, and jobsite/foot-traffic wear.
Specifications Table:
| Specification | Details |
|---|---|
| Sheet size | 4 ft x 8 ft |
| Thickness (nominal) | 1/4 in (6.4 mm) ± 1/16 in (1.6 mm) |
| Width tolerance | 4 ft (1219 mm) ± 1/8 in (3 mm) |
| R-value | 0.28 (°F•ft²•hr/BTU) |
| Flame spread & smoke developed | 0/0 (ASTM E84) |
| Mold resistance | 10/10 |
| Permeance | >30 perms (>1710 ng/Pa•s•m²) |
| Water absorption (max) | 5% |
| Surface water absorption (nominal) | 1.0 gram (both sides) |
| Compressive strength (nominal) | 900 psi |
| Flexural strength, parallel (min) | ≥40 lbf (178 N) |
| Bending radius | 4 ft (1219 mm) |
| Linear variation with change in temperature | 8.5 x 10^-6 in/in/°F (15.3 x 10^-6 mm/mm/°C) |
| Linear variation with change in moisture | 6.25 x 10^-6 |
| Flute spanability | 2-5/8 in (66.7 mm) |
| Standards / test methods referenced | ASTM C1177; ASTM C473; ASTM E84; ASTM E96; ASTM C518; ASTM E661 |
| Board type | Primed gypsum roof board / cover board |
| Construction | Fiberglass mat facer with high-density gypsum core |
Frequently Asked Questions (FAQ):
Q: What size and thickness is this board?
A: This product is a 4 ft. x 8 ft. sheet with a nominal 1/4 in. thickness.
Q: What types of roofing systems is it used with?
A: It is intended for mechanically fastened, adhered, and partially adhered roofing systems as a cover board and bonding surface.
Q: Is this board moisture resistant?
A: Yes—published performance notes up to 5% water absorption by weight and 1-gram nominal surface water absorption on both sides of the board.
Q: Does it have fire performance ratings?
A: Published data notes 0/0 flame spread/smoke developed (ASTM E84) and references FM Class 1 and UL Class A performance in assemblies.
Q: Is it compatible with roofing adhesives?
A: Yes—the enhanced/coated fiberglass facer is described as improving compatibility and performance with roofing adhesives, especially in fully adhered systems.
A sleek, high-performance foundation for the roofline
There’s a quiet luxury in materials that do the hard work beautifully—DensDeck Prime brings a crisp, primed surface and a refined, fiberglass-faced finish that elevates what’s beneath the membrane. Its high-density gypsum core is engineered for resilience, helping the roof assembly stand up to moisture, fire demands, and the wear of real-world conditions. Pair it with fully adhered systems when you want that confident, continuous bond and a cleaner build sequence. It’s the kind of unseen layer that makes the entire structure feel impeccably considered.
Choose DensDeck Prime 1/4 in. 4x8 to add a durable, moisture- and fire-conscious cover board layer that helps your roofing system perform longer.