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Johns Manville DynaBase HW Fiber Glass-Reinforced SBS Base or Ply Sheet, Black, 39-3/8 in. x 49 ft. 2 in.
Regular price $96.00Orders start at $399 — combine any items to reach the minimum. Learn more
Johns Manville DynaBase HW Fiber Glass-Reinforced SBS Base or Ply Sheet, Black, 39-3/8 in. x 49 ft. 2 in.
Johns Manville DynaBase HW is a fiber glass-reinforced base or ply sheet used in a variety of multi-ply roofing systems. The roll measures 39-3/8 in. x 49 ft. 2 in. and comes in Black with a fine mineral parting agent on top and a polyolefin burn-off film on the bottom for heat welding. Its SBS rubber and asphalt blend gives the sheet elasticity and installation ease.
Key Features:
- Base or ply use: Used as a fiber glass-reinforced base or ply sheet in a variety of multi-ply roofing systems.
- SBS elasticity: High-quality SBS rubber and asphalt blend lends elasticity and flexibility, with elongation and recovery that accommodate roof movement.
- Fiber glass mat: The fiber glass reinforcement mat offers excellent dimensional stability and tensile strength and withstands differential movement.
- No thermal memory: Because the mat has no thermal memory, less time is needed to relax the sheet, allowing easier installation.
- Heat weldable: A polyolefin burn-off film on the bottom side enables application using heat welding techniques.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | Johns Manville |
| Sell unit | 1 roll, 39-3/8 in. x 49 ft. 2 in. |
| Product line | DynaBase HW |
| Material | SBS rubber and asphalt blend with fiber glass reinforcement mat |
| Color / finish | Black, fine mineral parting agent on top side |
| Available colors | 1 color: Black |
| Dimensions | 39-3/8 in. x 49 ft. 2 in. per roll |
| Coverage per unit | Approximately 162 sq ft per roll before laps and waste |
| Intended use | Base or ply sheet in multi-ply (BUR and modified bitumen) roofing systems |
| Application method | Heat welding via polyolefin burn-off film on the bottom side |
Coverage & How Much You Need:
Each 39-3/8 in. x 49 ft. 2 in. roll covers roughly 162 sq ft of nominal area. Deduct specified side and end laps and add a waste allowance when calculating rolls per job.
Fit and Compatibility:
Designed for use within Johns Manville multi-ply roofing systems, typically under a granule-surfaced cap sheet such as DynaLastic 180 FR. Cap sheets, adhesives, primers and flashing materials are sold separately; follow the JM system specification for attachment.
Frequently Asked Questions (FAQ):
Q: What is included with this order?
A: One roll of DynaBase HW base or ply sheet, 39-3/8 in. x 49 ft. 2 in., in Black.
Q: How is this sheet applied?
A: The polyolefin burn-off film on the bottom enables heat welding application techniques.
Q: How much area does a roll cover?
A: A roll covers about 162 sq ft nominal; subtract laps and waste for net coverage.
Q: Why does no thermal memory matter?
A: The fiber glass mat has no thermal memory, so the sheet relaxes faster and installs more easily than mats that curl back.
Q: Can it serve as both base and ply?
A: Yes, DynaBase HW is designed for use as either a base or ply sheet in multi-ply systems.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
DynaBase HW is a workhorse base/ply sheet when the spec calls for fiber glass reinforcement and heat-weldable application. Its dimensional stability makes it forgiving on decks with differential movement, and the faster relaxation time can save labor on large fields. Pair it with an SBS cap sheet such as DynaLastic 180 FR to complete a compatible multi-ply assembly.
Heat welding involves open-flame or hot-air equipment; follow hot-work safety procedures, keep extinguishers on hand and use roof fall protection.
Order Johns Manville DynaBase HW fiber glass-reinforced base or ply sheet for your next multi-ply roof.
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