Johns Manville Dynaflex 36 in. x 25 ft White SBS Modified Bitumen Cap Sheet Roll

Johns Manville Dynaflex is a white SBS modified bitumen cap sheet supplied as a 36 in. x 25 ft roll covering 3/4 square. It serves as the top layer in a multi-ply low-slope roofing assembly and pairs with compatible JM base and interply sheets.

Key Features:

• SBS flexibility: SBS modified asphalt provides elongation and flexibility across temperature swings.
• White surfacing: White finish gives a clean, light-colored cap surface.
• Cap sheet role: Designed as the top membrane layer of a multi-ply low-slope roof.
• Easy sizing: 36 in. x 25 ft roll delivers 3/4 square per roll.
• System match: Part of the Johns Manville modified bitumen membrane family.

Specifications Table:

Coverage & How Much You Need:

One 36 in. x 25 ft roll covers 3/4 square. Allow for side and end laps when estimating rolls per roof area.

Fit and Compatibility:

Intended as the cap layer over Johns Manville SBS modified bitumen base and interply sheets in a multi-ply assembly. Base sheets, mastic, primers and fasteners are sold separately.

Frequently Asked Questions (FAQ):

Q: What is on the roll?
A: One roll of Dynaflex white cap sheet, 36 in. wide by 25 ft long, rated at 3/4 square per roll.

Q: How many rolls do I need?
A: Divide the roof area in squares by 3/4 and add extra for laps and waste.

Q: Is this a base sheet?
A: No, Dynaflex is a cap sheet intended as the top layer over a base or interply membrane.

Q: What color is it?
A: The listed item is White.

Q: How is it installed?
A: It is installed as part of a multi-ply assembly; follow the manufacturer’s application requirements for the chosen system.

Expert Verdict Reviewed by the SuperArbor Pro Desk

Dynaflex works as the weathering layer of a two- or three-ply SBS assembly; roll it over a compatible JM base sheet with proper laps and full embedment. Confirm the approved attachment method for the specific system specification before ordering. Order about 10 percent extra to cover end and side laps on low-slope roofs.

Hot or solvent-based installation methods carry burn and fire hazards; follow the manufacturer’s application instructions and site safety practices.

Order the Johns Manville Dynaflex white cap sheet roll for your low-slope roofing assembly.