I'm generally following the guidance in the Kollman Books
so the walls will be very thick indeed, 6"+ and yes, the goal is to get as high a rating as possible. I'm converting a large ice box to a refrigerator
. This has sort of been done before but only by making a small Starboard box inside the larger void. The new box will be properly insulated. There's generally not any other material available than these rigid insulations. Vacuum panels
have almost disappeared from the market completely.
Based on what information do you say Polyisocyanurate is very water permeable? Looking at the spec sheets
for Polyisocyanurate Water Absorpbtion rate os 0.05 and Styrofoam's is 0.1 according to the spec sheets (found here: Rigid Foam
) Skipmac's point about it being the system of installation
with two concrete walls that might be a problem, but I believe the ratings are for the material.
I have asked Dow about this myself too and they basically said... we don't recommend that for use in a marine
refrigerator. Which is the answer they will give for all of their products. They wouldn't engage in a more meaningful conversation. :-(
If they do answer you with regard to the water absorption rates being for the system or the material, I'd love to hear that.
I am planning on 6"-10" of insulation so at 3R for every 2" it would definitely.
Is that the big sheet in the workshop?
You have an interesting idea there too about mixing the types of insulation though... I should think about that.
(Disclaimer: /v Hello World and s/v Deep Playa share a workspace with two other boats in Ballard, WA)
Sounds like the basic answer though is only Jason is using this material and he's still in the design\construction phase... so no long-term users, at least not on this thread...