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Johns Manville GlasBase Plus Base or Ply Sheet, 36 in. x 106 ft. Roll
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Johns Manville GlasBase Plus Base or Ply Sheet, 36 in. x 106 ft. Roll
JM GlasBase Plus is a flexible SBS-modified base sheet with fiber glass reinforcement, intended as a base sheet in built-up roofing or as a base or intermediate ply in modified bitumen systems. This listing is one 36 in. x 106 ft. roll. It meets ASTM D 4601, Type II, and pairs with cold-process mastics such as JM BUR Adhesive.
Key Features:
- SBS asphalt blend: The SBS synthetic rubber and high-quality asphalt blend adds elasticity and flexibility, laying flat to virtually eliminate wrinkles.
- Fiber glass reinforcement: Fiber glass mat provides low moisture absorption, dimensional stability, and rot resistance as a replacement for organic base sheets.
- Fully-coated mat: No pinholes prevent asphalt bleed-through and eliminate splitting from excessive attachment to nailable decks.
- Nail retention: Excellent nail retention and resistance to uplift forces for secure base sheet attachment.
- Cold-process compatible: Non-porous composition allows use as a ply sheet with cold process mastics such as JM BUR Adhesive.
- ASTM compliant: Meets the requirements of ASTM D 4601, Type II.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | Johns Manville |
| Sell unit | 1 roll, 36 in. x 106 ft. |
| Product line | JM GlasBase Plus |
| Available sizes | 36 in. x 106 ft. roll |
| Material | SBS-modified asphalt with fiber glass reinforcement mat |
| Dimensions | 36 in. x 106 ft. |
| Coverage per unit | Approx. 318 sq. ft. per roll before laps |
| Surfacing | Fine mineral parting agent |
| Approvals | Meets ASTM D 4601, Type II |
| Application methods | Nailable deck attachment, cold process mastics such as JM BUR Adhesive |
| Intended use | Base sheet in BUR or base/intermediate ply in modified bitumen systems |
Coverage & How Much You Need:
One 36 in. x 106 ft. roll provides about 318 sq. ft. before side and end laps. Size the job from net roof area plus your specified lap allowances, and set base sheet attachment spacing per system requirements.
Fit and Compatibility:
For use as a base sheet in JM built-up roofing or as a base or intermediate ply in modified bitumen systems, including cold-process mastic systems such as JM BUR Adhesive. Cap sheets, adhesives, and flashing products are sold separately.
Frequently Asked Questions (FAQ):
Q: What is included?
A: One roll of JM GlasBase Plus, 36 in. x 106 ft.
Q: How much does one roll cover?
A: About 318 sq. ft. before laps; deduct your lap allowance for net coverage.
Q: Where is it used?
A: As a base sheet in built-up roofing or as a base or intermediate ply in modified bitumen systems.
Q: What standard does it meet?
A: It meets the requirements of ASTM D 4601, Type II.
Q: Can it be used with cold adhesives?
A: Yes, its non-porous composition allows use as a ply sheet with cold process mastics such as JM BUR Adhesive.
Q: How does it perform on nailable decks?
A: The fully-coated mat prevents asphalt bleed-through and provides excellent nail retention and uplift resistance.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
GlasBase Plus is a solid pick over organic base sheets on nailable decks because its fully-coated fiber glass mat holds nails well and resists bleed-through and splitting. Let the SBS-blend sheet relax after unrolling to take advantage of its wrinkle-free lay, and keep laps shingled correctly with the deck slope.
Use caution when cutting rolls and wear gloves; follow hot-work safety procedures if installing with heat.
Order the JM GlasBase Plus 36 in. x 106 ft. base sheet roll for your BUR or modified bitumen system.
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