R-value is a measure of thermal resistance used in the building and construction industry, which depends primarily on the type and thickness of the material.
The R-value of KERDI-BOARD as determined according to ASTM C518 is as follows:
3/16" (5 mm): 0.9
1/2" (12.5 mm): 2.2
2" (50 mm): 9.1This is based on independent lab test results, which are linear and can be used to calculate the R-value of other KERDI-BOARD thickness