The present invention provides a roofing product comprised of an asphalt coating on a nonwoven fiberglass mat. Enhanced tear strength for the roofing product, generally an asphalt shingle, is obtained by the presence of a release agent. The release agent can be a coating on the fiberglass mat, an additive in the mat binder, or present as an additive in the asphalt itself. Preferably, the release agent is a reactive polysiloxane which can react with any component within the roofing product, including the glass surface, sizing chemicals, binder chemicals, as well as the asphalt coating. The reaction can take place either during or after the polysiloxane is added or applied.