Do rigid polyurethane panels exist in the US?
Hi all — The Wikipedia list of insulation materials includes “polyurethane rigid panels” as one of the highest scoring materials. It reports R-6.8 per inch as the initial value for pentane-expanded polyurethane, and R-5.5 when aged 5-10 years (which is still about 38% higher than EPS).
Problem: I can’t find polyurethane panels at Home Depot, Lowe’s, or Menards. All I find are EPS, XPS, and polyiso.
Do polyurethane panels exist in the US market? If so, where are they sold?
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Those R value numbers are about right for polyiso. Polyiso is polyisocyanurate. Regular two-part spray foam is a type of polyurethane foam, which also has similar R values to polyiso. You might as well just go with polyiso since it’s readily available and offers essentially the same R value as the Wikipedia article gives to polyurethane foam.
Wikipedia even mentions that polyiso starts out similarly to polyurethane as a chemical compound, but has some different reactants to arrive at the different final product.
There's a guy near me selling factory seconds on Craigslist that he advertises as "basically spray foam in sheets." I don't know if that means polyiso or really polyurethane.
Those sheets look like polyiso to me. Usually one side will have some printing to tell you what it is, but I didn’t see that in his pic.
You could probably haggle his prices down a bit too. I usually see factory second 1/2” polyiso for around $5/sheet, for example.