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National Gypsum
DEXcell® Tech Guide

DEXcell® Tech Guide

Product catalog summary

Product Overview
DEXcell® Roof Boards are designed for commercial roofing, offering mold resistance and serving as coverboards or thermal barriers. The product line includes DEXcell Glass Mat Roof Board, DEXcell FA Glass Mat Roof Board, and DEXcell Cement Roof Board, each tailored for specific roofing systems and conditions.

DEXcell Glass Mat Roof Board
Ideal for mechanically fastened roof systems, this board provides fire and thermal barrier properties. It features coated fiberglass facers for enhanced handling and strength, is easy to score and snap, resists mold, and complies with ASTM C 1177 standards.

DEXcell FA Glass Mat Roof Board
Suited for fully adhered roof systems, this board serves as a fire and thermal barrier, features heavy-duty coated fiberglass facers, and meets FM Class 1 and UL Class A fire ratings.

DEXcell Cement Roof Board
Recommended for high-temperature applications, such as dark-colored membranes in southern climates, suitable for various roofing systems including modified bitumen and built-up roofs.

Typical Roof System Applications
A detailed table indicates the suitability of each DEXcell product for different roofing systems, such as single ply, modified bitumen, and vegetative roofs, based on performance and cost-effectiveness.

Recommendations and Limitations
Guidelines emphasize following manufacturer instructions and local codes to maintain warranty validity, keeping boards dry, and avoiding installation in adverse weather conditions.

Warranty
The warranty may be voided if products are used for non-recommended applications or if installation guidelines are not followed.

Specifications

DEXcell FA Glass Mat Roof Board: Features a coated fiberglass facer and high-density gypsum core, available in thicknesses of 1/4", 1/2", and 5/8".
DEXcell Cement Roof Board: Composed of Portland cement, lightweight aggregate, and glass mesh, available in 7/16" thickness.

Fire Resistance
Both products meet UL Class A fire ratings and comply with FM standards, tested for flame spread and smoke development, achieving a rating of 0/0.

Installation Guidelines
Boards must be kept dry, not installed in wet conditions, and covered by the final roof covering the same day. Proper fastener spacing is crucial for wind-uplift performance.

Performance Data

Flexural Strength: Varies by product and thickness, with DEXcell Cement Roof Board offering higher strength.
Water Absorption: Both products have a maximum absorption rate of less than 10%.
Compressive Strength: DEXcell Cement Roof Board has a nominal strength of 1250 psi.

Limitations
Moisture exposure can adversely affect performance and installation. Boards should not be stored on the ground and must be protected from moisture.

Conclusion
DEXcell Roof Boards provide robust solutions for various roofing systems, with specific installation and handling requirements to ensure optimal performance.

Design Recommendations
National Gypsum does not warrant the design or quality of other components in a roof assembly. Excess moisture, heat, or pressure can negatively impact performance.

Application Limitations
Outlines limitations for adhesives, primers, and installation methods, stressing the importance of avoiding excess loads and moisture.

Installation Recommendations
Proper installation techniques are crucial, including the use of approved mechanical fasteners and ensuring roof boards are covered by the membrane system the same day.

Storage Recommendations
DEXcell products must be kept dry and stored properly to prevent moisture buildup. Immediate removal of plastic packaging and covering with a breathable, waterproof material is advised.

Warranty Information
Details a limited warranty covering defects in material and workmanship, with specific conditions for claims, excluding liability for indirect or consequential damages.

Mold and Moisture Resistance
DEXcell Roof Boards are designed to resist mold and mildew, achieving a high score in ASTM D 3273 testing, but no material is mold-proof, emphasizing the importance of avoiding water exposure.

Catalog excerpts

Roof Board DEXceir FA Glass Mat Roof Boards DEXceir Glass Mat Roof Boards DEXceir Cement Roof Boards Technical Guide

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Table of Contents SECTION PAGE Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 DEXcell Glass Mat Roof Board . . . . . . . . . . . . . . . . . . . . . . . . . . 4 DEXcell FA Glass Mat Roof Board . . . . . . . . . . . . . . . . . . . . . . . 6 DEXcell Cement Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Typical Roof System Applications . . . . . . . . . . . . . . . . . . . . . . 10 Recommendations, Limitations . . . . . . . . . . . . . . . . . . . . . . . . 14 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . ....

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National Gypsum Company® (“National Gypsum”) has provided the following Product Recommendations and Limitations as guidance for the recommended use, installation and storage of its DEXcell® brand Roof Board products, including without limitation, DEXcell® Glass Mat Roof Board, DEXcell® FA Glass Mat Roof Board, and DEXcell® Cement Roof Board. DEXcell roof products typically constitute one component of a multi-component roof assembly and it is possible that for any given project, the project’s roof design professional, the roof system manufacturer, or any applicable design or construction code...

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DEXcell® brand Glass Mat Roof Board is a mold resistant gypsum board designed for use as a coverboard and/ or thermal barrier in commercial roofing applications. DEXcell Glass Mat Roof Board is ideally suited for mechanically fastened roof systems. DEXcell Glass Mat Roof Board is a fire barrier and thermal barrier manufactured with coated fiberglass facers and an enhanced mold resistant gypsum core. It is produced in 1/4", 1/2", and 5/8" thicknesses and 4' wide in 4' and 8' lengths. DEXcell Glass Mat Roof Board scores and cuts easily and is specially coated on the front, back and sides for easy...

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2. Georgia-Pacific data taken from GP literature, Item #622602 - 8/14 Technical Data Fire Resistance Thickness, nominal 1/4" (6.4 mm) 1/2" (12.7 mm) 5/8" (15.9 mm) Width, standard 4' (1219 mm) 4' (1219 mm) 4' (1219 mm) Length, standard 4', 8' (1219, 2438 mm) 4', 8' (1219, 2438 mm) 8' (2438 mm) Weight, nominal, lbs./sq. ft. (kg/m2) 1.2 (5.9) 2.0 (10) 2.5 (12) Surfacing Coated Fiberglass Facer Coated Fiberglass Facer Coated Fiberglass Facer Flexural Strength1, parallel, lbf. min. (N) ≥40 (178) ≥80 (356) ≥100 (445) Flute Spanability2 2-5/8" (67 mm) 5" (127 mm) 8" (203 mm) Permeance3, Perms (ng/Pa.S.m2)...

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Heavy Duty Coated Glass Mat DEXcell® brand FA Glass Mat Roof Board is a mold resistant gypsum board designed for use as a coverboard and/or thermal barrier in commercial roofing applications. DEXcell FA Glass Mat Roof Board is ideally suited for fully adhered roof systems. DEXcell FA Glass Mat Roof Board is a fire barrier and thermal barrier manufactured with heavy duty coated fiberglass facers and an enhanced mold resistant gypsum core. It is produced in 1/4", 1/2", and 5/8" thicknesses and 4' wide in 4' and 8' lengths. DEXcell FA Glass Mat Roof Board scores and cuts easily and is specially...

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Fiberglass Mesh Reinforced Edge DEXcell brand Cement Roof Board is a lightweight moisture and mold resistant cement board designed for use as a coverboard and/or thermal barrier in all commercial roofing applications. ® DEXcell Cement Roof Board is a fire barrier and thermal barrier manufactured of Portland cement, lightweight aggregate and glass mesh that provides an exceptionally hard, durable surface that is able to withstand prolonged exposure to moisture. It is produced in 7/16" thickness and 4' wide in 4' and 8' lengths. Basic Uses DEXcell Cement Roof Boards are ideally suited for a wide...

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PRODUCT COMPARISON Thickness, nominal 7/16" (11.1 mm) Width, standard 4' (1219 mm) Length, standard 4', 8' (1219, 2438 mm) Weight, nominal, lbs./sq. ft. (kg/m2) 2.1 (10.3) Flexural Strength1, psi >1000 Flute Spanability2 12" (304 mm) Permeance3, Perms (ng/Pa.S.m2) >5 (287) R Value4, ft2 ˚F hr/BTU (m2 K/W) .28 Linear Variation with Change in Moisture5 ≤0.07% Water Absorption6, % Max. <10 Compressive Strength, psi Nominal 1250 Flame Spread, Smoke Developed (ASTM E 84) 0/0 Bending Radius 5' (1524 mm) 7/16" 1/2" DEXcell Cement Securock Cement Performance Roof Board Roof Board Flexural Strength, parallel,...

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Typical Roof System Applications The following are examples of typical roof system applications using DEXcell Roof Boards and should be considered to be for illustration purposes only. Consult with the roof system manufacturer or roof design professional for their recommendations of use and installation. National Gypsum Company does NOT provide roof design services, and makes no warranties or representation with respect to any particular roof system or any components or materials, other than DEXcell Roof Boards. It is the responsibility of the roof system manufacturer or roof design professional...

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Thermal Barrier/Vapor Barrier Membrane Vapor Retarder DEXcell FA Glass Mat Roof Board DEXcell FA Glass Mat Roof Board DEXcell FA Glass Mat Roof Board Asphaltic Membrane DEXcell Glass Mat Roof Board Steel Deck Parapet Wall Framing DEXcell FA Glass Mat Roof Board Steel Deck DEXcell Cement Roof Board Hot Asphalt Ribbon/Spot Mopping DEXcell Glass Mat Roof Board Steel Deck

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