Just an observation - when you go to view - edit snap grid, the snap grid spacing comes up in SI units even if you're set to english. If you just hit, say, 0.5, and hit enter, it'll take it as 0.5 m, even if you're set to english units; so you've got to specify "0.5 ft", and it will end up in ft, but when you go back to the menu to change it again, it'll show you 0.1524 m.
Once again, screenshot attached. You can see the "EN" button depressed, as well as the floors in the navigation column on the left shown in "ft".
thanks!