EPDM stands for Ethylene-propylene-diene monomer. It is a type of rubber, and is most commonly used as a low slope roofing system. EPDM is very durable, and has great resistance to tearing, solvents, and high temperatures (it maintains its flexibility at both high and low temperatures).

Commonly, EPDM roofs are applied as a 1-ply system, with just one layer of EPDM over insulation. They can either be ballasted, mechanically attached (with screws or nails), or adhered (with glues). Most EPDM is black in color, although they can be painted to reduce solar gain.