There are three ways to install an EPDM rubber roof: adhered, mechanically fastened or ballasted. Each installation method has its own benefits and uses. An adhered system means the roof is glued to the surface beneath it. The most common EPDM system is mechanically attached, with fasteners that are screwed into the deck through the insulation. Ballasted systems are laid over the insulation and kept in place by smooth, river-washed stone or concrete pavers.