The retaining wall Rvalue consists of the Rvalue of the wall itself and the Rvalue of the ground behind the retaining wall.
The calculator on this page calculates the Rvalue of the ground behind the wall. To calculate the Rvalue of the complete wall select "complete wall insulation" in the "Insulation" dropdown box below. Then in the "Insulation Rvalue" cell enter any additional Rvalues such as the Rvalue of the wall structure itself (concrete, insulation, strapping, etc.). This "Insulation Rvalue" includes everything which is in addition to the ground itself.
What to enter in the "Insulation Rvalue" cell:
 If you want to be "superaccurate" you could enter R0.06 for a 100mm concrete wall or R0.14 for 200mm concrete blocks although these values are well within the limits of accuracy of this calculator and also of any other slab floor and retaining wall calculations such as NZS4214.
 If you have a complete layer of polystyrene as insulation you can simply enter that Rvalue in the "Insulation Rvalue" cell.
 If you have a wall with strapping, insulation and lining you would first calculate the Rvalue of those components using the Floor, Wall and Roof Rvalue Calculator page and then enter that construction Rvalue in the "Insulation Rvalue" cell below.
This calculator simply adds the retaining ground Rvalue and the "Insulation Rvalue" together.
Note: The actual retaining wall heat losses are very complex. This calculator provides an approximate value only.
