Using VW 2020.
Using the slab and slab drainage tools to model a roof. I've created roof components in the assembly as follows:
3" Polyiso at R5.1/inch
4" EPS at R4.04/inch
Based solely on the insulation, that gives me a quick calc of R31, if the roof was flat.
I've set the roof drains for a 2% slope with the EPS layer as the "sloped" component.
The object info tells me the R value is R39. It must take into account added sloped insulation, but it's not clear. I'm guessing the 4" EPS I set in the assembly is the minimum and it's automatically added insulation to achieve the proper slopes. Can anyone confirm?