ASTM D6162, D6163 and D6164 (SBS Modified Bitumen)

ASTM D6162, D6163 and D6164 are a family of ASTM International specifications for SBS-modified bituminous sheet materials, the rubber-modified asphalt membranes widely used in multi-ply low-slope roofing and waterproofing. SBS (styrene-butadiene-styrene) is a thermoplastic elastomer that makes asphalt more flexible, especially in cold weather.

The three standards differ mainly in the reinforcement inside the sheet:

• ASTM D6162 – reinforced with a combination of polyester fabric and glass fibre. Active version: D6162/D6162M-21.
• ASTM D6163 – reinforced with glass fibre.
• ASTM D6164 – reinforced with polyester.

Each covers prefabricated sheets, with or without mineral granule surfacing, intended for multiple-ply roofing and waterproofing membranes.

Why reinforcement matters

• Polyester reinforcement gives high elongation and puncture resistance, so the membrane can stretch with building movement.
• Glass fibre gives dimensional stability and resists shrinkage but stretches less.
• Combination reinforcement aims to balance the two.

Designers choose base sheets and cap sheets with different reinforcements to suit deck movement, traffic and climate.

Typical properties

The specifications set limits for properties such as thickness, mass, tensile strength, elongation, tear strength, low-temperature flexibility, dimensional stability, compound stability (resistance to flow at high temperature) and granule adhesion.

Installation methods

SBS sheets can be applied in hot asphalt, with cold adhesives, as self-adhered sheets, or by torch application (for torchable products). Field performance and fire and wind ratings are system properties tested separately (for example under FM 4470, UL 1897 and ASTM E108).

History and related standards

Polymer-modified bitumen membranes were developed in Europe in the mid-1960s and have been in common use in the United States since about 1975. APP (atactic polypropylene) modified sheets, which are usually torch-applied, are covered by companion ASTM specifications. In Europe, reinforced bitumen sheets for roof waterproofing are specified under a harmonised European standard.