Patents by Inventor Paul F. Friesen

Paul F. Friesen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Positively vented flat roof system
    Patent number: 4538388
    Abstract: A double cuspated surface plastic film is positioned between the base of a roof structure and the roof covering material so as to provide a multitude of venting air passages under the roof covering.
    Type: Grant
    Filed: February 7, 1983
    Date of Patent: September 3, 1985
    Assignee: Armstrong World Industries, Inc.
    Inventor: Paul F. Friesen