VIP and Phenolic insulation

I know that VIP and phenolic are interesting because of their high R values, but they have other drawbacks to consider. VIP’s are not strong. They are brittle. Some products using VIP’s sandwiched with other types of insulation have been developed to mitigate the inherent physical limitations of VIP’s, resulting in a thicker assembly without a much better R value. I believe that they are still very pricy, as are phenolics. Suggest you research the physical properties and pricing of VIP’s and phenolics before specifying. Best of luck.