The R value is a measure of the insulation value of a complete wall from internal plaster to exterior surface.  Brick veneer is typically less than 0.8.

For Unitex Base Board 50mm, the R value is: 2.08 (including sisalation)

For Unitex Base Board 75mm, the R value is: 2.62 (including sisalation)

For Unitex Base Board 100mm, the R value is: 3.2 (including sisalation)