Closed-Cell Spray Foam is Revolutionizing Energy Efficiency -- As Amazing as That Sounds (Part 2)

By Katie McVay

If you tuned in last week, you know we were starting to discuss closed-cell spray polyurethane insulation, and how -- because of increased awareness and industry acceptance -- it's starting to become the insulation of choice for many builders, architects and homeowners. In future posts we'll get into the nitty-gritties of foam: its application and many benefits. But right now, let's discuss exactly what closed-cell spray foam is:

What is Closed-Cell Spray Foam?

Closed-cell spray polyurethane foam is a medium-density insulating material that can be used in a variety of applications in residential and commercial buildings. It is especially beneficial in exterior cavity walls, roof decks, cathedral ceilings and attics to increase the performance of the building envelope.

Closed-cell spray polyurethane has an average insulating value of R-6 to R-7 per inch and an average weight of two pounds per cubic foot when fully cured, hence the product's industry nickname, "two pound spray." Once sprayed onto a substrate, it expands about 35 to 50 times its original volume to form a rigid plastic with a compressive strength of between 15 and 25 psi. The "closed-cell" name comes from the fact that the cell structure of the foam is closed, disallowing air and moisture to pass through it. Heavier, more-dense closed-cell spray foams, those with weights of 3, 4 or 5 pounds per cubic foot, are typically used for exterior roofing applications. The majority of closed-cell spray foams use HCFCs (hydrochlorofluorocarbons) or HFCs (hydroflurocarbons) as the blowing agent. However, newer generations of blowing agents are more environmentally conscious: some, such as Enovate 3000, have a zero Ozone Depletion Potential (ODP) and a low Global Warming Potential (GWP). Also, this particular product is not considered a Volatile Organic Compound (VOC) in the United States. 

The majority of closed-cell spray foams use fossil fuels as their main ingredient. However, more and more manufacturers -- in response to the desire for more environmentally friendly alternatives -- are starting to incorporate renewable resources and recycled materials into their products. The renewable resource soy is a good example of a product that alot of manufacturers, including this one, are starting to use.

Stay tuned next week when we discuss how closed-cell spray foam is applied. In future posts we'll discuss the many benefits of this type of foam.