Ask about adding helical piers to the newer foundation or perhaps mud- or foam-jacking under it. 

Originally posted by @Jon S.:Have

The condition of the property is a big part of whether you can shave that percentage down or not. 

I tried cabinet rescue with a mini foam roller in white and got as good as sprayed results.

Maybe injection foam insulation is the answer but what if I do that and it doesn’t work?

Looks like they put on some sort of foam board for the backing.

I'm having foam sprayed into a section of a rehab this morning.

I am in the process of fixing this by replacing the vapor barrier with new plastic sheathing, replacing the fiberglass with foam boards, and air sealing the entire crawl including the exterior vents, and creating an air tight and insulated entrance door.

You can then strap furring strips over the insulation (attached through the insulation into the masonry) and hang drywall or resilient channel and then drywall from the furring.Polyisocyanurate foil faced rigid foam runs ~R6/inch, while closed cell spray foam runs R6 to R6.4 and provides a better air barrier.Alternatively, you could stand-up a 2x3 or 2x4 studwall in-front of the masonry wall (leave a 1/2" gap between the masonry wall and the studs and spray the stud cavities (and space behind the studs) with closed cell spray foam.  

They used to have a machine that was like and plainer with a spinning drum blade on the bottom that you pushed along and it would literally shave off the first layer of the floor.