glamis, mine is 12'-2 1/2" at the top of the satillite dome--- i've got a sign on my dash that says CLEAR-- 12' 4" i'd say if you could go 13' on the door or what ever the next increment over 12' 6" in door height from your door co. ya' don't have to open it all the way --- but i'm thinkin' that might be a better deal than jackin' the shop up OR lettin' the air out of the tires-----mase