New Cork Spray, Same Old Hokum? – GreenBuildingAdvisor

I am a member of a soon-to-be built condominium project in Zone 4B where, because the builder is not comfortable putting a layer of EPS over plywood/under stucco,  some members have gotten interested in using spray cork.  I know this has been discussed here in 2023 (https://www.greenbuildingadvisor.com/question/cork-insulation) and in 2019 (https://www.greenbuildingadvisor.com/question/cork-spray-with-specific-wall-assembly) and the consensus was that the claims for cork spray were “pure hogwash”).  Now there’s a new company out of Arizona making rather vague claims about cork’s physical qualities without actually saying how it will improve building performance: https://greencorkproducts.com/

To me, the song remains the same.  As far as reducing heat transfer:

convection: 1/8 of an inch is too thin to add more than  0.5 of R value. 

conduction: it only applies to the wall assembly, which will already have two coats of stucco over housewrap.

radiation: even if it were somehow a radiant barrier,  it’s not going to reduce emissivity from summer heat if it’s applied directly over stucco.

I don’t know if the compressibility of cork could provide some resistance to cracking over and above some other elastomeric coating, but the company doesn’t go quite that far, saying only this: “Excellent Elasticity and Compressibility: It is the only solid which, when compressed on one side, does not increase in volume on another; and as a result of its elasticity, it is able to adapt, for example, to variations in temperature and pressure without suffering alterations.”

From what I have heard, the informal marketing pitch (not anything written down) is that is reduces heat gain in the Arizona desert.  A 1/8 inch layer that reduces heat gain without talking about emissivity or reflectivity seems highly doubtful to me. 

I would appreciate any objective evaluations of this product I can pass on to my fellow members.