Ethylene Propylene Diene Monomer (EPDM)

Thermoset membranes incorporate principal polymers that are chemically cross linked or cured. One characteristic of true polymers is once they are cured, they only can be bonded to similiar materials with adhesives.

The most common thermoset roof membrane is EPDM.  EPDM principally is composed of two compounds, ethylene and propylene, that are derived from oil and natural gas. Contractors commonly call these membranes "rubber" roofs.