Is Using Closed-Cell Foam Worth the Trade-Offs?
This insulation material is popular for its high R-value and good air-sealing and vapor-blocking properties, but cost, health, and environmental concerns cause some builders to have second thoughts.
Synopsis: Contributing editor Michael Maines takes a detailed look at closed-cell spray foam, which is growing in popularity as an insulation material. Maines identifies its advantages—a high R-value per inch, a capacity for air-sealing and for blocking water-vapor movement, and its enhancement of the framing-to-sheathing connection. He then discusses its disadvantages—including high cost, messiness and potential health risks, and the fact that it can’t be used in many transitional areas where air leakage is high. But Maines focuses primarily on closed-cell foam as a contributor to global warming because of the blowing agent that is used in most closed-cell foams, which is over a thousand times worse than carbon dioxide.
Closed-cell polyurethane spray foam is amazing stuff. It’s a great insulator, with a higher R-value per inch than almost any other commonly available material. (Polyisocyanurate foam can be equivalent, but it varies with product and temperature.) When…