Jo Ann, you are right -- I looked too quickly and thought that he had lowered the house relative to the garage, but I see that their floors are at the same levels. In the mean time, I tried your method with a sample and it works. I don't know about patching with wedges or soffits -- need to learn that. I'll probably experiment some more, then break the garage away, rebuild it, raise it, and move it to the house with your method. Thanks for the help.
Dan