Mechanical Case Studies


Trex, Inc. manufactures a recycled decking product that is made from waste plastic and sawdust. The product can be used like lumber but is more resistant to weathering. Mr. Ronald Nystrom received U.S. Patent 5,474,831 for a crowned wooden deck board that allows water to run off and is easy to walk upon. Nystrom accused Trex, Inc., of patent infringement in a series of three separate, but related, lawsuits starting in the year 2000. Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, defended Trex and hired Trident’s expert witnesses to support the technical aspects of the case.

Trident’s experts discovered numerous examples of prior art and took precise measurements of the top surfaces of deck boards to refute Nystrom’s claims. Statistical analysis of the measurements was performed, and the opinions of the opposition experts were successfully refuted. Trex’s manufacturing process was analyzed to refute Nystrom’s claims that Trex was intentionally violating his patent.


On September 4, 2009, a unanimous Federal Circuit panel affirmed a district court ruling
of non-infringement for Finnegan client Trex, in Nystrom v. Trex (2009-1026). Trex has now prevailed in three separate district court proceedings, and all three decisions have been affirmed by the Federal Circuit, confirming Trex’s right to make its composite decking products free of Nystrom’s claims of infringement.

Trident’s Experts

Donald W. Vannoy

  • Analysis of measurements

Dennis J. Hurley, ME

  • Analysis of measurements

Field measurements of prior art

Electronic measurement system with custom designed fixture in use at opposition attorney’s office