This is all great information
I have been toying with this insulation question for my build I'm about to start
Looking around the web has shown that the r value of pink insulation runs at about 8 per inch.
this is info from Prodex Insulaion
Technical Data Prodex Total Insulation
ICC-ES Recognized #ESR-2350 (4’x175’ roll only) and Energy Star Qualified
R Values
Heat Flow DOWN Heat Flow DOWN (roof/ceiling)
One (1) layer of Prodex * 15.67
Two (2) layers of Prodex * 21.10
Heat Flow HORIZONTAL Heat Flow HORIZONTAL (wall)
One (1) layer of Prodex * 7.00
Two (2) layers of Prodex * 9.58
Heat Flow UP Heat Flow UP (crawl space)
One (1) layer of Prodex * 6.00
Two (2) layers of Prodex * 8.24
* 1/2-inch to 3-inch airspace recommended for optimal performance. The above testing consisted of applying Prodex with an airspace of 2.64 inch on each side of product.
One Layer of ProdexTwo Layers of Prodex
Test method ASTM 1116. Interior side of Product was exposed.
2x6 Wood-frame Assembly 24 inch.
Hope it helps