Closed-cell spray foam and XPS: green or not?
I’ve posted several times on my pretty badly compromised attic. We live in a 50s ranch outside Chicago with a ceiling that has been butchered by can lights and an AC handler & ductwork. I feel the only reasonable solution is to move the conditioned envelope to the roof. I’ve debated and debated and debated this because the solutions are expensive, a pain to implement, and now it appears environmentally questionable.
Yesterday I was about to place an order for many thousands of dollars of CC spray foam. Then I came across articles describing the GWP of these products. I’m really struggling with how I feel about this.
I have a few questions:
1) The articles I read are ~7 years old. Are these blowing agents still being used? Are there commercially available CC spray options that are more “green”? And do they perform as well?
2) I understand that these blowing agents have >1,000x the greenhhouse effect of CO2 but is the volume of the gases being released significant? I would feel a lot better if someone could tell me that the GW contribution of my sprayfoam solution was equivalent to (for example) the methane produced in a year by 2 1/2 cows. I guess what is the scale of this problem?
BTW, I received bids from several contractors to apply 6″ of Polyiso above the roof deck and re-shingle and gutter. This option was cost prohibitive. I feel very stuck between sprayfoam or leaving the problem be.
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