Hi Shellvet, I have been planning to use spray cork on the interior on my 72' Boler
for some time. I believe there is a minor R value, 8 seems to come to mind, somewhere I read. As for condensation I am not sure. Depending on a quote, i may elect to rent a hopper and spray it myself. The one issue I am looking into is how much will the coating raise the interior surface and how textured will it be. These are concerns I have for when I go to replace the windows
and gaskets. I may need to tape off a 1/4" or so around the openings to ensure the right thickness and it's not built up to much for the gasket.
Here is a link https://www.corkco.ca/