A door wall is a sliding-glass door or patio door. The term is yet another example of banal Michigan vernacular, where in the residents latch on to company names, trademark names, marketing terms and product names from local companies. The terms become embedded in the local vocabulary and eventually become accepted as actual valid words and phrases. In this case the term comes from Wallside Windows in Taylor, MI (a large window manufacturer), where 'door wall' is their created word for sliding-glass door.
"Bob! John's gonna bring over them doorwalls from Wallsides on Tuesdee afternoon 'round two-thirty. Get 'er done!"
a sliding glass door
I call it a doorwall because I'm from Detroit and I don't know any better!
A sliding glass door
I ran into the doorwall because I didn't see the glass.
The thing that holds a door onto a wall.
Hey dude I walked into a door wall again.