EPDM is a rubber material whose principal components consist of the compounds ethylene and propylene. A flexible rubber matrix forms when a small amount of cyclopentadiene(the "catalyst") is added to the mix.It has been available in a cured (vulcanized) state. It is only recently that EPDM has been available as a liquid.

Ethylene Propylene Diene Monomer (or Terpolymer which is simply a product consisting of three distinct monomers). The can contains the ethylene and propylene (plus a pigment) in a solvent. The "catalyst" is the diene which when added to the ethylene and propylene form a chemical reaction. The product is pure EPDM rubber. There are no additives in the product.

EPDM is classified as a Thermoset material which means it is either fully-cured prior to being installed or that as liquid EPDM it cures during natural weathering after installation. EPDM roofs are single-ply membranes meaning there is only one ply of roofing material, not multiple plies laminated together.

EPDM has been in use on roofs in the USA since the 1960's and is one of the most common types of low-slope roofing materials. This is because it is relatively inexpensive, simple to install, and fairly clean to work with when compared to conventional built-up roofs.

Liquid Rubber® is a unique form of EPDM Rubber. As a liquid it can conform to any shape of roof, flashing, or protrusion, vertical or horizontal, and can be applied easily with a paintbrush, roller, or airless sprayer for larger areas. When mixed with a catalyst it cures by chemical reaction to form a self-adhering seamless sheet.

EPDM rubber has been used in sheet form for more than 30 years. It is probably the most durable roofing product ever developed. Liquid Rubber is identical chemically to the sheet EPDM but with the distinct advantage of being a liquid. Because Liquid Rubber and vulcanized EPDM have identical chemical composition, they have very similar performance characteristics.

EPDM rubbers have a long history of reliability in automotive and industrial applications. Radiator hoses in cars and gaskets on freezer doors are made of EPDM rubber. This illustrates its true ability to perform in extreme environments.