EPDM, TPO, and modified bitumen differ in composition, seam construction, and repair compatibility. Understanding those differences is more useful than treating every flexible sheet as the same kind of rubber.

What to check first

  • Compare seam methods as well as surface appearance.
  • Identify any coating that covers the original membrane.
  • Keep product selection specific to the confirmed surface.

Identify the roof before selecting a product

  1. Use reliable identification

    Look for installation records, membrane markings, or a qualified assessment. Color alone cannot reliably distinguish EPDM, TPO, PVC, or a coated asphalt surface.

  2. Identify any previous coating

    The material a sealant touches may be an old coating rather than the roof membrane. Product compatibility must account for that exposed layer.

  3. Confirm the current repair detail

    Review the manufacturer’s instructions for both the substrate and the type of defect. An installation demonstration is not a substitute for a suitable localized repair method.

Watch the field examples

These archive demonstrations show individual projects. Use the current guidance above and Bergstrom’s published instructions if an older video shows a different product or method. Torch work shown in installation videos is professional work.

Watch Three Common Flat Roof Membranes and Their Repair NeedsOpens on YouTube ↗

From the project archive

Flat Roof Rubber Membrane - Modified bitumen mop Down roof
Historical project photo · Flat Roof Doctor
Flat Roof Illinois
Historical project photo · Flat Roof Doctor

Product reference: Bergstrom Industries’ published knowledge catalog. Follow the latest product label and safety information. Historical project examples are educational and are not a specification for every roof.