I had an Insulspan quote pulled together by an outfit in NH called Panel Pros for a SIPs roof. The guys I talked to there were great, very informative and took the time to answer all of my questions. One thing though caught me off guard and you need to know about this in case the outfit you may be working with is doing the same thing.
Insulspan has a list of published R-values available on their website. When I had Panel Pros quote the job, they included a Word document with their quote about going with Insulspan SIPs and what to expect. You'll find it
here. It lists R-values that are around 12% higher than the numbers furnished by Insulspan's website. You'll find these in a PDF by going
here. I asked Panel Pros about the disparity and discovered something interesting: they were giving me outdated R-values for SIPs that had been tested at 25F, when they should've been giving me R-values tested at 70F (which is what code requires for EPS SIPs.) Going with the 25F measurements is a clever way to massage these R-values and to make it look like one company's panels have a particular edge over another's.
I don't know who's to blame, whether it's just a simple oversight, or whether any of that is even relevant. Just know though that when you're looking at R-values for EPS SIPs you need to make sure that those numbers are based on 70F measurements to be able to compare them equally with everyone else's. Panel Pros has assured me that they're updating their documentation to reflect this. And I have no doubts that they will.
John