I am looking to have a 20'x24' unheated detached garage built on the slope of my property. The back of the garage would have about 5' high foundation above soil, with blocks stepped along the sides as needed, plus the parking slab. Then a typical wood garage framed on top. I live in MN where the frost line is typically down to 42". Both of the companies I have gotten the most comprehensive bids from do not propose to do a frost footing, but only use strip footings, concrete blocks and bond beam. I asked about whether a frost footing should be done and they said that this foundation would basically act as a floating foundation and move together. A frost footing could be done for another 4k they replied after asking. Other concrete professionals (who focused on flatwork only so didn't bid) suggested that I should not allow anyone to not do a frost footing. Everything I can find online only speaks to monolithic slabs being floating. Can someone who does this type of block work in cold climates help with this quandry of whether a frost footing is needed structurally?