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GAF DEXcell FA Glass Mat Roof Board – Gypsum Cover Board, 4 ft x 8 ft and 4 ft x 4 ft, Multiple Thicknesses
Regular price $32.75Orders start at $399 — combine any items to reach the minimum. Learn more
GAF DEXcell FA Glass Mat Roof Board – Gypsum Cover Board, 4 ft x 8 ft and 4 ft x 4 ft, Multiple Thicknesses
GAF DEXcell FA Glass Mat Roof Board is a gypsum cover board with heavy-duty coated fiberglass facers for use as a substrate board, thermal barrier, or insulation cover board in commercial roofing. Five sizes are offered, from 1/4 in. x 4 ft x 4 ft to 5/8 in. x 4 ft x 4 ft. Sold per piece.
Key Features:
- Moisture resistant: Gypsum core with coated fiberglass facers meets or exceeds ASTM C1177 for moisture resistance.
- Mold resistant: Meets ASTM G21 and ASTM D3273 for mold resistance.
- Sealed surface: Precoated facers help improve membrane adhesive coverage and performance versus systems with no cover board.
- May skip primer: May eliminate the need for a field primer per the applicable GAF system specification manual.
- Easy handling: Scores and cuts easily; coated on front, back, and sides to reduce fiber fly and irritation.
- Fire protection: Can serve as a UL Class A thermal barrier and provides increased fire resistance pursuant to ANSI/UL 790.
- Impact protection: As a cover board, protects the membrane from traffic and hail or impact damage pursuant to FM 44702.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | GAF |
| Sell unit | 1 panel |
| Product line | GAF DEXcell FA Glass Mat Roof Board |
| Available colors | White |
| Available sizes | 1/4 in. x 4 ft x 4 ft; 1/4 in. x 4 ft x 8 ft; 1/2 in. x 4 ft x 4 ft; 1/2 in. x 4 ft x 8 ft; 5/8 in. x 4 ft x 4 ft |
| Material | Gypsum core with heavy-duty coated fiberglass (glass mat) facers |
| Thickness | 1/4 in., 1/2 in., or 5/8 in. |
| Dimensions | 4 ft x 4 ft or 4 ft x 8 ft panels |
| Approvals | ASTM C1177 (moisture), ASTM G21 and D3273 (mold), ANSI/UL 790 (fire resistance), FM 44702 (impact/hail protection), UL Class A thermal barrier |
| Intended use | Substrate board, thermal barrier, and/or insulation cover board for commercial roofing |
Coverage & How Much You Need:
Each panel covers 16 sq. ft. (4 ft x 4 ft) or 32 sq. ft. (4 ft x 8 ft); divide roof area by panel coverage, allowing for layout waste at edges.
Fit and Compatibility:
Works in adhered single-ply, modified bitumen, liquid-applied membrane or coatings, spray foam, and metal roofing systems, and under vapor retarders. Consult the applicable GAF system specification manual for priming and assembly details.
Frequently Asked Questions (FAQ):
Q: What thicknesses and sheet sizes are available?
A: Five options: 1/4 in. and 1/2 in. in 4 ft x 4 ft and 4 ft x 8 ft sheets, plus 5/8 in. in 4 ft x 4 ft.
Q: How much area does one sheet cover?
A: A 4 ft x 4 ft sheet covers 16 sq. ft.; a 4 ft x 8 ft sheet covers 32 sq. ft.
Q: Do I need a primer under the membrane?
A: DEXcell FA's precoated facers may eliminate the need for a field primer – consult the applicable system specification manual.
Q: What is it used for?
A: As a substrate board, thermal barrier, or insulation cover board protecting the membrane from traffic, hail, and impact.
Q: Which roofing systems can it be used in?
A: Adhered single-ply, modified bitumen, liquid-applied systems and coatings, spray foam, and metal roofs.
Q: How does it handle on site?
A: It scores and cuts easily and is coated on all faces to reduce fiber fly and irritation.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
Match thickness to the system requirement – 1/4 in. is common as a minimum cover board, while thicker panels add thermal-barrier and impact performance. Because the precoated faces improve adhesive coverage, keep faces clean and dry, stagger joints, and confirm primer needs against the specific system specification before mobilizing.
Gypsum panels are heavy – use two-person lifts or mechanical handling and wear gloves and eye protection when cutting.
Order GAF DEXcell FA Glass Mat Roof Board in your choice of five sizes for tough, moisture-resistant cover board protection.
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