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Johns Manville GlasTite Flexible Base Ply or Flashing Sheet, 36 in. x 50 ft Roll
Regular price $247.00Orders start at $399 — combine any items to reach the minimum. Learn more
Johns Manville GlasTite Flexible Base Ply or Flashing Sheet, 36 in. x 50 ft Roll
Johns Manville GlasTite Flexible is a base sheet, ply sheet and flashing membrane for built-up roofing, supplied as a 36 in. x 50 ft roll. Its fiber glass/polyester composite reinforcement mat delivers flexibility and high tensile strength, and imprinted lay lines help installers maintain proper exposure across multiple plies.
Key Features:
- Three roles: Intended for use as a base sheet, ply sheet, or flashing membrane in built-up roofing systems.
- Flexible reinforcement: Fiber glass/polyester composite reinforcement mat provides superior flexibility and conformability for quick installation.
- High tensile strength: Exceptionally high tensile strength delivers superior protection against splitting plus excellent puncture resistance.
- Flashing ready: Conformability makes it ideal for tight flashing systems at parapet walls, skylights, penetrations, drains and vents.
- Lay lines: Imprinted lay lines on the top surface help maintain proper exposure and correct ply count.
- ASTM compliance: Meets the requirements of ASTM D 4601, Type II.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | Johns Manville |
| Sell unit | 1 roll, 36 in. x 50 ft |
| Product line | GlasTite Flexible |
| Dimensions | 36 in. x 50 ft |
| Material | Asphalt felt sheet with fiber glass/polyester composite reinforcement mat |
| Surfacing | Fine mineral parting agent |
| Coverage per unit | 150 sq ft nominal per roll before laps |
| Approvals | Meets the requirements of ASTM D 4601, Type II |
| Intended use | Base sheet, ply sheet, or flashing membrane in built-up roofing systems |
Coverage & How Much You Need:
One 36 in. x 50 ft roll provides 150 sq ft of nominal coverage before laps. For base-sheet application, follow the specified lap and fastening pattern (JM fastening-pattern details are available for various attachment methods); for plies, use the lay lines to set exposure.
Fit and Compatibility:
Use within Johns Manville built-up roofing systems as a base sheet, ply sheet or flashing membrane, including at parapets, skylights, penetrations, drains and vents. Mopping asphalt, fasteners and cap sheets are sold separately.
Frequently Asked Questions (FAQ):
Q: What is included in one order?
A: One roll of GlasTite Flexible, 36 in. wide by 50 ft long.
Q: How much roof does one roll cover?
A: About 150 sq ft nominal before laps; deduct for side and end laps per specification.
Q: Can it be used for flashing?
A: Yes; its flexibility and conformability make it well suited to tight flashing systems at parapet walls, skylights, penetrations, drains and vents.
Q: How do I keep my ply exposure correct?
A: Imprinted lay lines on the top surface guide proper exposure and the correct number of plies.
Q: What standard does it meet?
A: It meets the requirements of ASTM D 4601, Type II.
Q: Is it fastened or mopped?
A: It is used in built-up roofing; base-sheet attachment follows the specified fastening patterns or adhesive methods for the system.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
GlasTite Flexible is a go-to sheet when one product must serve as base sheet, interply and flashing felt in a BUR system, simplifying stock on mixed-detail jobs. Let the roll relax before unrolling, and use the lay lines to hold exposure consistent across the crew. For demanding flashing details, take advantage of its conformability rather than forcing a stiffer ply sheet into corners.
Built-up roofing installation involves hot asphalt or torch-adjacent work and hot surfaces; use appropriate PPE and follow the system's installation and fire-safety requirements.
Order the JM GlasTite Flexible 36 in. x 50 ft roll for a versatile BUR base, ply and flashing sheet.
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