EPS FANFOLD SHEATHING IN WARRANTED GENFLEX ROOFING SYSTEMS
To better meet the needs of our customers, Holcim Solutions and Products US, LLC will allow the use of EPS Fanfold sheathing (“Fanfold”) in qualifying warranted GenFlex roofing systems. Fanfold must be Type VIII with a minimum thickness of 1/2″ (12.7 mm) and must meet the following minimum physical properties:
Minimum Physical Properties | ||
| Property | ASTM Test Method | Type VIII |
| Compressive Strength | D1621 | 13 psi (90 kPa) |
| Density (Nominal) | C 303 | 1.25 pcf (20 kg/m^3) |
| Moisture Vapor Transmission | E96 | <1 perm (<57.5 ng/(Pa•s•m^2)) |
| Water Absorption | C272 | <1% by volume |
Fanfold is allowed for Mechanically Attached applications of GenFlex EZ TPO membrane systems. Existing gravel surfaced roofs should be spud/scraped clean and vacuumed. Existing single-ply membranes should be cut into 10 ft x 10 ft grids before attaching Fanfold with GenFast #12 Insulation Fasteners or GenFast #14 Fasteners and GenFlex insulation plates.
Attachment Rates for EPS Fanfold Sheathing (Per 32 Square Feet) | ||
| Approved Systems | Deck Type and Minimum Fastening Rate | |
| Steel | Plywood/OSB/Wood Plank | |
| Mechanically Attached TPO (60-mil Min) | 5 | 5 |
NOTES:
- InvisiWeld™ applications are not allowed when Fanfold is the immediate substrate.
- Damaged or wet components of the existing roofing system must be replaced.
- Fanfold must have a suitable facer. “Bare” EPS must never come in direct contact with residual asphalt.
- Gray and Tan TPO membrane should not be installed over existing asphalt and EPDM systems when Fanfold is used in lieu of a GenFlex insulation and/or cover board.
- Adjacent Fanfold sheets should be laid parallel and staggered every 2.0′ (0.6 m).
- For projects requiring performance validation, switch to an appropriate GenFlex insulation and/or cover board.
- Check with local building code authorities for requirements for partial tear-offs and recovers.
- Wind speeds up to 72 MPH may be approved based on project characteristics. Hail and Cut & Puncture Protection are not available when Fanfold is used in lieu of a GenFlex insulation and/or cover board.
For more information, contact your Holcim Regional Technical Coordinator at 800-443-4272.