This is what our son Michael and I managed to get done this evening. We're going with a two inch thick Foamular rigid foam insulation, and 2x4 framing and drywall in front of it. When we're done well have a combined insulation rating of R12.55. That's a combination of the R10 for the rigid foam, R1.11 for the cinder blocks, R1 for the air space, and R0.45 for the drywall. All of the joints are taped with Tyvek tape, and we'll be laying a bead of low expansion foam insulation along the bottom of the rigid foam to fill any gap by the floor.
Next we'll be starting on the framing. Once that's up, we'll move the home gym over to this area and start the whole process again. Two more areas to go after that, then we'll take care of plumbing, electrical, and drywall. This is going to take a while, folks!