IRON SENTRY is a product line of MCPU Polymer Engineering LLC, the manufacturers. Contracting is done through a network of qualified installers who are located locally and are a different legal entity from MCPU. Under the direction of our president, Dr. Thomas Garrett, our team of Ph.D. chemists has perfected the state of the art polyurethane roof coating. Dr. Garrett and his staff, in an effort to follow the lead of the EPA, were able to remove all Mercury from the formula and retain the resilience that made IRON SENTRY revolutionary while at the same time increasing the physical strength of the product.


  • Sentry SpecTM. Free CSI Format Specifications from Manufacturer.
  • Mercury-free polymer.
  • A manufacturing facility that has produced over 350 million pounds of polyurethane.
  • Comprehensive Applicator Reliability Program.
  • Installation by Factory Trained Applicators.
    Note: this will NOT occur on your roof, but on the ground in our manufacturing facilities.
  • Warranty offered directly from Manufacturer (see warranty for details) assures IRON SENTRY will Stand Guard over your roof for many years to come.
  • Iron Sentry White is CRRC registered.

Thomas Garrett, Ph.D. President
Tom Garrett is President of MCPU Polymer Engineering, the manufacturer of IRON SENTRY. MCPU has been manufacturing the polymers used in polyurethane since the late 1950’s. Dr. Garrett holds a B.S. with honors from Stanford University and a Ph.D. from the University of California at Berkeley, both in chemistry. Prior to joining MCPU, Dr. Garrett was a postdoctoral fellow at the Univertsite Louis Pasteur in Strasbourg, France. The author of over 30 papers and patents, Dr. Garrett is a graduate of Harvard Business School in Boston, a Senior Member of the American Society for Quality, a Fellow of the American Institute of Chemists, and a Paul Harris Fellow of Rotary International. A more detailed biography can be found in America and Who’s Who in Science and Technology. Tom resides in Corona, California with his wife Karen and his two sons.