ASTM D4637

ASTM D4637/D4637M, Standard Specification for EPDM Sheet Used In Single-Ply Roof Membrane, sets minimum quality requirements for ethylene propylene diene terpolymer (EPDM) roofing membranes. EPDM is a synthetic rubber and one of the oldest single-ply roofing materials in North America. The active version is D4637/D4637M-15 (reapproved 2021, with an editorial change).

Types

The specification recognizes three types of sheet:

• Type I – non-reinforced rubber sheet, the most common form, usually black.
• Type II – sheet with internal fabric or scrim reinforcement, often used for mechanically attached systems.
• Type III – fabric-backed sheet, where a fleece or fabric is bonded to the underside, often for adhered systems.

What it covers

The standard covers flexible EPDM sheet for single-ply roofing exposed to the weather. Tests and property limits set minimum quality levels for properties such as thickness, tensile strength, elongation, tear resistance, brittleness at low temperature, ozone resistance, heat ageing and weathering.

It excludes in-place roof design factors including fire resistance, field seam strength, material compatibility and uplift resistance. Those depend on the whole roof system and are addressed through system tests and codes.

About EPDM roofing

EPDM is a thermoset: it is cured during manufacture and cannot be heat-welded. Seams are made with adhesives or factory-applied seam tapes. EPDM is flexible over a wide temperature range and resists ultraviolet light and ozone well. Black EPDM absorbs heat; white-surfaced versions exist for cooler roofs.

Because it does not leach plasticizers, EPDM is also used for pond liners and rainwater harvesting roofs.

Related standards

• ASTM D6878 (TPO) and ASTM D4434 (PVC) cover thermoplastic membranes.
• In Europe, EPDM roofing sheet is specified under a harmonised European standard for plastic and rubber roof waterproofing sheets.