R-8 Phenolic Foam Boardstock Insulation Is Back

Back in 1985, when I started what is now BuildingGreen and was working for a construction company part-time (yes, I had to make a living), I remember installing a type of foil-faced foam insulation that was then being promoted as the highest-R-value insulation on the market. It was Koppers’ Exceltherm, which I think was advertised as providing R-8.2 per inch. It was a phenolic foam insulation material—foamed phenol formaldehyde. Adding this much insulation to the 175-year-old home we were restoring made a huge difference in improving comfort and reducing heating bills.

In early 1989, Koppers (which was also known as Beazer East, Inc.) sold its phenolic foam insulation business to Johns Manville Corporation, which manufactured phenolic foam roof insulation until 1992. By that time, problems with corrosion of metal in contact with the phenolic foam came to light, and Johns Manville and Beazer East were hit with a class-action lawsuit that ended production of the material.