The chart you cite is for the above ground framing.
R value concrete wall basement.
Concrete block makes a cost effective and structurally sound wall but it has.
You are confusing the minimum thickness of foam on the outside of above ground framing with the code required r value for basement wall insulation using foam.
By doubling the thickness of the wall to 16 inches the r value only increases by 0 50.
A wall s thermal resistance or its r value is its ability to slow the transfer of heat from one side to the other.
These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation.
For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3.
Zones 3 and 4 include the midwest and northern regions requiring r 10 to r 19 values.
The department of energy provides a service to determine the exact r value required based on zip code and type of heating fuel.
Consider adding insulation to the outside of the basement wall this can serve as protection for your waterproofing also.
Generally zones 1 and 2 cover the southern states which suggest no necessary values to r 10 for basement walls.
The cool concrete of the foundation wall will collect humid air which will condense on its surface.
The code cited by martin is for basement walls.