I am setting up my 18 X 9 Intex pool on a 12 X 22 concrete slab. I want to put something under it for insulation and to protect from the concrete degrading the liner. I currently plan to put 1/2 inch extruded foam board. (Owens Corning FOAMULAR 1/2 in. x 4 ft. x 8 ft. R-3 Square Edge Rigid...
